The Strong Protective Effect of Circumcision against Cancer of the Penis

Male circumcision protects against cancer of the penis, the invasive form of which is a devastating disease confined almost exclusively to uncircumcised men. Major etiological factors are phimosis, balanitis, and high-risk types of human papillomavirus (HPV), which are more prevalent in the glans penis and coronal sulcus covered by the foreskin, as well as on the penile shaft, of uncircumcised men. Circumcised men clear HPV infections more quickly. Phimosis (a constricted foreskin opening impeding the passage of urine) is confined to uncircumcised men, in whom balanitis (affecting 10%) is more common than in circumcised men. Each is strongly associated with risk of penile cancer. These findings have led to calls for promotion of male circumcision, especially in infancy, to help reduce the global burden of penile cancer. Even more relevant globally is protection from cervical cancer, which is 10-times more common, being much higher in women with uncircumcised male partners. Male circumcision also provides indirect protection against various other infections in women, along with direct protection for men from a number of genital tract infections, including HIV. Given that adverse consequences of medical male circumcision, especially when performed in infancy, are rare, this simple prophylactic procedure should be promoted

Vortex states in 2D superconductor at high magnetic field in a periodic pinning potential

The effect of a periodic pinning array on the vortex state in a 2D superconductor at low temperatures is studied within the framework of the Ginzburg-Landau approach. It is shown that attractive interaction of vortex cores to a commensurate pin lattice stabilizes vortex solid phases with long range positional order against violent shear fluctuations. Exploiting a simple analytical method, based on the Landau orbitals description, we derive a rather detailed picture of the low temperatures vortex state phase diagram. It is predicted that for sufficiently clean samples application of an artificial periodic pinning array would enable one to directly detect the intrinsic shear stiffness anisotropy characterizing the ideal vortex lattice.Comment: 8 pages, 5 figure

Uganda's HIV Prevention Success: The Role of Sexual Behavior Change and the National Response

There has been considerable interest in understanding what may have led to Uganda's dramatic decline in HIV prevalence, one of the world's earliest and most compelling AIDS prevention successes. Survey and other data suggest that a decline in multi-partner sexual behavior is the behavioral change most likely associated with HIV decline. It appears that behavior change programs, particularly involving extensive promotion of “zero grazing” (faithfulness and partner reduction), largely developed by the Ugandan government and local NGOs including faith-based, women’s, people-living-with-AIDS and other community-based groups, contributed to the early declines in casual/multiple sexual partnerships and HIV incidence and, along with other factors including condom use, to the subsequent sharp decline in HIV prevalence. Yet the debate over “what happened in Uganda” continues, often involving divisive abstinence-versus-condoms rhetoric, which appears more related to the culture wars in the USA than to African social reality

A Surprising Prevention Success: Why Did the HIV Epidemic Decline in Zimbabwe?

Daniel Halperin and colleagues examine reasons for the remarkable decline in HIV in Zimbabwe, in the context of severe social, political, and economic disruption

Collective Particle Flow through Random Media

A simple model for the nonlinear collective transport of interacting particles in a random medium with strong disorder is introduced and analyzed. A finite threshold for the driving force divides the behavior into two regimes characterized by the presence or absence of a steady-state particle current. Below this threshold, transient motion is found in response to an increase in the force, while above threshold the flow approaches a steady state with motion only on a network of channels which is sparse near threshold. Some of the critical behavior near threshold is analyzed via mean field theory, and analytic results on the statistics of the moving phase are derived. Many of the results should apply, at least qualitatively, to the motion of magnetic bubble arrays and to the driven motion of vortices in thin film superconductors when the randomness is strong enough to destroy the tendencies to lattice order even on short length scales. Various history dependent phenomena are also discussed.Comment: 63 preprint pages plus 6 figures. Submitted to Phys Rev

Male circumcision, religion, and infectious diseases: an ecologic analysis of 118 developing countries

BACKGROUND: Both religious practices and male circumcision (MC) have been associated with HIV and other sexually-transmitted infectious diseases. Most studies have been limited in size and have not adequately controlled for religion, so these relationships remain unclear. METHODS: We evaluated relationships between MC prevalence, Muslim and Christian religion, and 7 infectious diseases using country-specific data among 118 developing countries. We used multivariate linear regression to describe associations between MC and cervical cancer incidence, and between MC and HIV prevalence among countries with primarily sexual HIV transmission. RESULTS: Fifty-three, 14, and 51 developing countries had a high (>80%), intermediate (20–80%), and low (<20%) MC prevalence, respectively. In univariate analyses, MC was associated with lower HIV prevalence and lower cervical cancer incidence, but not with HSV-2, syphilis, nor, as expected, with Hepatitis C, tuberculosis, or malaria. In multivariate analysis after stratifying the countries by religious groups, each categorical increase of MC prevalence was associated with a 3.65/100,000 women (95% CI 0.54-6.76, p = 0.02) decrease in annual cervical cancer incidence, and a 1.84-fold (95% CI 1.36-2.48, p < 0.001) decrease in the adult HIV prevalence among sub-Saharan African countries. In separate multivariate analyses among non-sub-Saharan African countries controlling for religion, higher MC prevalence was associated with a 8.94-fold (95% CI 4.30-18.60) decrease in the adult HIV prevalence among countries with primarily heterosexual HIV transmission, but not, as expected, among countries with primarily homosexual or injection drug use HIV transmission (p = 0.35). CONCLUSION: Male circumcision was significantly associated with lower cervical cancer incidence and lower HIV prevalence in sub-Saharan Africa, independent of Muslim and Christian religion. As predicted, male circumcision was also strongly associated with lower HIV prevalence among countries with primarily heterosexual HIV transmission, but not among countries with primarily homosexual or injection drug use HIV transmission. These findings strengthen the reported biological link between MC and some sexually transmitted infectious diseases, including HIV and cervical cancer

Electron spin dynamics in quantum dots and related nanostructures due to hyperfine interaction with nuclei

We review and summarize recent theoretical and experimental work on electron spin dynamics in quantum dots and related nanostructures due to hyperfine interaction with surrounding nuclear spins. This topic is of particular interest with respect to several proposals for quantum information processing in solid state systems. Specifically, we investigate the hyperfine interaction of an electron spin confined in a quantum dot in an s-type conduction band with the nuclear spins in the dot. This interaction is proportional to the square modulus of the electron wave function at the location of each nucleus leading to an inhomogeneous coupling, i.e. nuclei in different locations are coupled with different strength. In the case of an initially fully polarized nuclear spin system an exact analytical solution for the spin dynamics can be found. For not completely polarized nuclei, approximation-free results can only be obtained numerically in sufficiently small systems. We compare these exact results with findings from several approximation strategies.Comment: 26 pages, 9 figures. Topical Review to appear in J. Phys.: Condens. Matte

Review: A critical evaluation of arguments opposing male circumcision for HIV prevention in developed countries

A potential impediment to evidence-based policy development on medical male circumcision (MC) for HIV prevention in all countries worldwide is the uncritical acceptance by some of arguments used by opponents of this procedure. Here we evaluate recent opinion-pieces of 13 individuals opposed to MC. We find that these statements misrepresent good studies, selectively cite references, some containing fallacious information, and draw erroneous conclusions. In marked contrast, the scientific evidence shows MC to be a simple, low-risk procedure with very little or no adverse long-term effect on sexual function, sensitivity, sensation during arousal or overall satisfaction. Unscientific arguments have been recently used to drive ballot measures aimed at banning MC of minors in the USA, eliminate insurance coverage for medical MC for low-income families, and threaten large fines and incarceration for health care providers. Medical MC is a preventative health measure akin to immunisation, given its protective effect against HIV infection, genital cancers and various other conditions. Protection afforded by neonatal MC against a diversity of common medical conditions starts in infancy with urinary tract infections and extends throughout life. Besides protection in adulthood against acquiring HIV, MC also reduces morbidity and mortality from multiple other sexually transmitted infections (STIs) and genital cancers in men and their female sexual partners. It is estimated that over their lifetime one-third of uncircumcised males will suffer at least one foreskin-related medical condition. The scientific evidence indicates that medical MC is safe and effective. Its favourable risk/benefit ratio and cost/benefit support the advantages of medical MC

Finite-Size Effects and Dynamical Scaling in Two-Dimensional Josephson Junction Arrays

In recent years many groups have used Fisher, Fisher, and Huse (FFH) dynamical scaling to investigate and demonstrate details of the superconducting phase transition. Some attention has been focused on two dimensions where the phase transition is of the Kosterlitz-Thouless-Berezinskii (KTB) type. Pierson et al. used FFH dynamical scaling almost exclusively to suggest that the dynamics of the two-dimensional superconducting phase transition may be other than KTB-like. In this work we investigate the ability of scaling behavior by itself to yield useful information on the nature of the transition. We simulate current-voltage (IV) curves for two-dimensional Josephson junction arrays with and without finite-size-induced resistive tails. We find that, for the finite-size effect data, the values of the scaling parameters, specifically the transition temperature and the dynamical scaling exponent z, depend critically on the magnitude of the contribution that the resistive tails make to the IV curves. In effect, the values of the scaling parameters depend on the noise floor of the measuring system.Comment: 24 pages, 8 figures; submitted to Physical Review

Pairing fluctuations and pseudogaps in the attractive Hubbard model

The two-dimensional attractive Hubbard model is studied in the weak to intermediate coupling regime by employing a non-perturbative approach. It is first shown that this approach is in quantitative agreement with Monte Carlo calculations for both single-particle and two-particle quantities. Both the density of states and the single-particle spectral weight show a pseudogap at the Fermi energy below some characteristic temperature T*, also in good agreement with quantum Monte Carlo calculations. The pseudogap is caused by critical pairing fluctuations in the low-temperature renormalized classical regime $\omega < T$ of the two-dimensional system. With increasing temperature the spectral weight fills in the pseudogap instead of closing it and the pseudogap appears earlier in the density of states than in the spectral function. Small temperature changes around T* can modify the spectral weight over frequency scales much larger than temperature. Several qualitative results for the s-wave case should remain true for d-wave superconductors.Comment: 20 pages, 12 figure