Rolling friction of a viscous sphere on a hard plane

A first-principle continuum-mechanics expression for the rolling friction coefficient is obtained for the rolling motion of a viscoelastic sphere on a hard plane. It relates the friction coefficient to the viscous and elastic constants of the sphere material. The relation obtained refers to the case when the deformation of the sphere $\xi$ is small, the velocity of the sphere $V$ is much less than the speed of sound in the material and when the characteristic time $\xi/V$ is much larger than the dissipative relaxation times of the viscoelastic material. To our knowledge this is the first ``first-principle'' expression of the rolling friction coefficient which does not contain empirical parameters.Comment: 6 pages, 2 figure

Toward a geography of black internationalism: Bayard Rustin, nonviolence and the promise of Africa

This article charts the trip made by civil rights leader Bayard Rustin to West Africa in 1952, and examines the unpublished ‘Africa Program’ which he subsequently presented to leading American pacifists. I situate Rustin’s writings within the burgeoning literature on black internationalism which, despite its clear geographical registers, geographers themselves have as yet made only a modest contribution towards. The article argues that within this literature there remains a tendency to romanticize cross-cultural connections in lieu of critically interrogating their basic, and often competing, claims. I argue that closer attention to the geographies of black internationalism, however, allows us to shape a more diverse and practiced sense of internationalist encounter and exchange. The article reconstructs the multiplicity of Rustin’s black internationalist geographies which drew eclectically from a range of Pan-African, American and pacifist traditions. Though each of these was profoundly racialized, they conceptualized race in distinctive ways and thereby had differing understandings of what constituted the international as a geographical arena. By blending these forms of internationalism Rustin was able to promote a particular model of civil rights which was characteristically internationalist in outlook, nonviolent in principle and institutional in composition; a model which in selective and uneven ways continues to shape our understanding of the period

Survival pending revolution:Self-determination in the age of proto-neo-liberal globalization

In 1971, the Black Panther Party (BPP) seemingly went through an ideological transformation. Between 1968 and 1970 the Party had forged strong national and international solidarity and support through a politics of revolutionary armed self-defence and a commitment to anti-imperialism. Yet, in late 1970 as the sands of both national and geo-politics shifted, and as allies, both at home and abroad, became less supportive, the Panthers found themselves on less solid ground. Black Panther leader Huey P Newton, realizing this shift in the political landscape, and the futility of attempting an armed insurgency against the state without widespread support, now steered the BPP towards the idea of ‘Survival Pending Revolution’. This saw the Panthers abandon the idea of immediate armed insurrection against the state and reorient towards a focus on their community engagement ‘survival programs’. This article argues that Newton’s orientation of the BPP away from armed insurrection and towards survival pending revolution was not simply a pragmatic choice of strategy, but rather based on a theorization of what he dubbed reactionary intercommunalism. Moreover, the article suggests that the history of neo-liberal globalization can be complicated and expanded by viewing Newton as one of the first theorists of neo-liberal globalization, and BPP survival programs as one of the first responses to the on-coming era of neo-liberalism in the US.</p

Modifying effect of dual antiplatelet therapy on incidence of stent thrombosis according to implanted drug-eluting stent type

Aim To investigate the putative modifying effect of dual antiplatelet therapy (DAPT) use on the incidence of stent thrombosis at 3 years in patients randomized to Endeavor zotarolimus-eluting stent (E-ZES) or Cypher sirolimus-eluting stent (C-SES). Methods and results Of 8709 patients in PROTECT, 4357 were randomized to E-ZES and 4352 to C-SES. Aspirin was to be given indefinitely, and clopidogrel/ticlopidine for ≥3 months or up to 12 months after implantation. Main outcome measures were definite or probable stent thrombosis at 3 years. Multivariable Cox regression analysis was applied, with stent type, DAPT, and their interaction as the main outcome determinants. Dual antiplatelet therapy adherence remained the same in the E-ZES and C-SES groups (79.6% at 1 year, 32.8% at 2 years, and 21.6% at 3 years). We observed a statistically significant (P = 0.0052) heterogeneity in treatment effect of stent type in relation to DAPT. In the absence of DAPT, stent thrombosis was lower with E-ZES vs. C-SES (adjusted hazard ratio 0.38, 95% confidence interval 0.19, 0.75; P = 0.0056). In the presence of DAPT, no difference was found (1.18; 0.79, 1.77; P = 0.43). Conclusion A strong interaction was observed between drug-eluting stent type and DAPT use, most likely prompted by the vascular healing response induced by the implanted DES system. These results suggest that the incidence of stent thrombosis in DES trials should not be evaluated independently of DAPT use, and the optimal duration of DAPT will likely depend upon stent type (Clinicaltrials.gov number NCT00476957

British Black Power:The anti-imperialism of political blackness and the problem of nativist socialism

The history of the US Black Power movement and its constituent groups such as the Black Panther Party has recently gone through a process of historical reappraisal, which challenges the characterization of Black Power as the violent, misogynist and negative counterpart to the Civil Rights movement. Indeed, scholars have furthered interest in the global aspects of the movement, highlighting how Black Power was adopted in contexts as diverse as India, Israel and Polynesia. This article highlights that Britain also possessed its own distinctive form of Black Power movement, which whilst inspired and informed by its US counterpart, was also rooted in anti-colonial politics, New Commonwealth immigration and the onset of decolonization. Existing sociological narratives usually locate the prominence and visibility of British Black Power and its activism, which lasted through the 1960s to the early 1970s, within the broad history of UK race relations and the movement from anti-racism to multiculturalism. However, this characterization neglects how such Black activism conjoined explanations of domestic racism with issues of imperialism and global inequality. Through recovering this history, the article seeks to bring to the fore a forgotten part of British history and also examines how the history of British Black Power offers valuable lessons about how the politics of anti-racism and anti-imperialism should be united in the 21st century.</p

Evaluation of the effect of different Dates of Sowing Regimes in Chickpea against Legume Pod Borer, Helicoverpa armigera (Hubner)

Effect of different sowing dates on chickpea crop and varietal factors against the incidence of legume pod borer Helicoverpa armigera, pod damage and yield were studied at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Hyderabad, Telangana during the post rainy seasons of 2019-20, and 2020-21. Ten Chickpea genotypes were sown at monthly intervals during first weeks of September, October and November. Each entry was sown in a 6 row plots, with 10 x 30 cm spacing. There were four replications in a split plot design. Among the different sowing regimes tested, November sown crop was found to be optimal and right time for sowing of the chickpea genotype to evade the pod borer coincidence. The borer population fluctuated with the change in dates of sowing. Pod borer population was higher in the early sown crop (September) and with delayed dates of sowing in October and November population decreased. There were significant differences in percent pod damage across genotypes ranging from 10.50 to 40.66 per cent. Minimum pod damage was observed in ICCV 10 and maximum pod damage was observed in ICC 3137. The grain yield ranged from 316.4 kg/ha to 836.1 kg/ha. The highest grain yield was recorded in ICCV 10 and lowest in ICC 3137. Correlation results of pod borer incidence in ICC 3137 showed positive correlation with maximum, minimum temperature and solar radiation, while rainfall and humidity were negatively correlated. Screening the different chickpea genotypes for resistance or tolerance to H. armigera allowed us in detection of a resistant/tolerant varieties which has shown the minimum level of damage in pods and further for ensuring higher yield with less pod borer damage, November is the optimal time for sowing of Chickpea

Queering Development? The Unsettling Geographies of South–South Cooperation

This paper deploys queer theory as a way of approaching South–South Cooperation (SSC). It examines the ways in which Southern development partners are not simply up-ending the long-standing spatialities, imaginaries and identities (re)produced through the mainstream international development regime, but queering terminologies and definitions, while presenting themselves in fluid ways, enrolling different identities and attributes in different places and to different audiences. At the same time, a queer lens reveals the (re)inscription of gendered, sexualised and racialised identities and hierarchies through the relationships, intimacies and practices of SSC. The paper proposes that queer theory can offer productive insights into the complex and compelling phenomenon of SSC, and the transgressive challenges to the postcolonial hierarchies and binaries of “traditional” international development

A Decolonial Critique of the Racialized “Localwashing” of Extraction in Central Africa

Responding to calls for increased attention to actions and reactions “from above” within the extractive industry, we offer a decolonial critique of the ways in which corporate entities and multinational institutions draw on racialized rhetoric of “local” suffering, “local” consultation, and “local” culpability in oil as development. Such rhetoric functions to legitimize extractive intervention within a set of practices that we call localwashing. Drawing from a decade of research on and along the Chad–Cameroon Oil Pipeline, we show how multiscalar actors converged to assert knowledge of, responsibility for, and collaborations with “local” people within a racialized politics of scale. These corporate representations of the racialized “local” are coded through long-standing colonial tropes. We identify three interrelated and overlapping flexian elite rhetoric(s) and practices of racialized localwashing: (1) anguishing, (2) arrogating, and (3) admonishing. These elite representations of a racialized “local” reveal diversionary efforts “from above” to manage public opinion, displace blame for project failures, and domesticate dissent in a context of persistent scrutiny and criticism from international and regional advocates and activists