The Bracero Program in the Arkansas Delta: The Power held by Planter Elite

This paper examines the Bracero Program and its implementation from the start of World War II to the end of the program in 1964. Farmers and planters in America needed a sufficient labor supply once the war started, and Mexico became the main supplier. The Bracero Program was initiated as a war effort and meant to only last until the end of the war, but the planter elite had far different intentions once they realized how productive and inexpensive the program could be. This paper identifies the leading causes for how the Bracero Program was able to last over twenty years

A Phase Ambiguity Resolution Technique for TCM

This paper presents the simulation model, performance evaluation and hardware implementation of a technique to resolve phase ambiguity in trellis coded modulation (TCM) where the popular Viterbi algorithm is utilized. While this approach has been employed with BPSK and QPSK, its application to multilevel modulation schemes (M\u3e4) is novel and of interest because it provides a viable alternative to rotationally invariant codes. This approach does not require any arithmetic computations and can be accomplished with minimal hardware. The results presented in this paper are being used to implement a 32 sector phase quantized TCM system utilizing 8PSK modulation

Transmission of electricity from wave power devices

This report assesses the problems likely to be encountered in transmitting bulk electrical energy from a source tens of kilometers offshore to the mainland of the United Kingdom

Actionable Neural Representations: Grid Cells from Minimal Constraints

To afford flexible behaviour, the brain must build internal representations that mirror the structure of variables in the external world. For example, 2D space obeys rules: the same set of actions combine in the same way everywhere (step north, then south, and you won't have moved, wherever you start). We suggest the brain must represent this consistent meaning of actions across space, as it allows you to find new short-cuts and navigate in unfamiliar settings. We term this representation an `actionable representation'. We formulate actionable representations using group and representation theory, and show that, when combined with biological and functional constraints - non-negative firing, bounded neural activity, and precise coding - multiple modules of hexagonal grid cells are the optimal representation of 2D space. We support this claim with intuition, analytic justification, and simulations. Our analytic results normatively explain a set of surprising grid cell phenomena, and make testable predictions for future experiments. Lastly, we highlight the generality of our approach beyond just understanding 2D space. Our work characterises a new principle for understanding and designing flexible internal representations: they should be actionable, allowing animals and machines to predict the consequences of their actions, rather than just encode

Electrical Generation Systems Suitable for use in Wave Power Schemes

This note describes studies made on electrical generation systems which may be suitable for wave power stations. Two complementary systems are described and the results of testing are presented. Computer simulations of each system which were used both at the design stage and during testing are also described

Sexually Transmitted Infections among HIV-1-Discordant Couples

INTRODUCTION:More new HIV-1 infections occur within stable HIV-1-discordant couples than in any other group in Africa, and sexually transmitted infections (STIs) may increase transmission risk among discordant couples, accounting for a large proportion of new HIV-1 infections. Understanding correlates of STIs among discordant couples will aid in optimizing interventions to prevent HIV-1 transmission in these couples. METHODS:HIV-1-discordant couples in which HIV-1-infected partners were HSV-2-seropositive were tested for syphilis, chlamydia, gonorrhea, and trichomoniasis, and HIV-1-uninfected partners were tested for HSV-2. We assessed sociodemographic, behavioral, and biological correlates of a current STI. RESULTS:Of 416 couples enrolled, 16% were affected by a treatable STI, and among these both partners were infected in 17% of couples. A treatable STI was found in 46 (11%) females and 30 (7%) males. The most prevalent infections were trichomoniasis (5.9%) and syphilis (2.6%). Participants were 5.9-fold more likely to have an STI if their partner had an STI (P<0.01), and STIs were more common among those reporting any unprotected sex (OR = 2.43; P<0.01) and those with low education (OR = 3.00; P<0.01). Among HIV-1-uninfected participants with an HSV-2-seropositive partner, females were significantly more likely to be HSV-2-seropositive than males (78% versus 50%, P<0.01). CONCLUSIONS:Treatable STIs were common among HIV-1-discordant couples and the majority of couples affected by an STI were discordant for the STI, with relatively high HSV-2 discordance. Awareness of STI correlates and treatment of both partners may reduce HIV-1 transmission. TRIAL REGISTRATION:ClinicalTrials.gov NCT00194519

HSV suppression reduces seminal HIV-1 levels in HIV-1/HSV-2 co-infected men who have sex with men.

OBJECTIVES: Suppressive herpes simplex virus (HSV) therapy can decrease plasma, cervical, and rectal HIV-1 levels in HIV-1/HSV-2 co-infected persons. We evaluated the effect of HSV-2 suppression on seminal HIV-1 levels. DESIGN: Twenty antiretroviral therapy (ART)-naive HIV-1/HSV-2 men who have sex with men (MSM) in Lima, Peru, with CD4 >200 cells/microl randomly received valacyclovir 500 mg twice daily or placebo for 8 weeks, then the alternative regimen for 8 weeks after a 2-week washout. Peripheral blood and semen specimens were collected weekly. Anogenital swab specimens for HSV DNA were self-collected daily and during clinic visits. METHODS: HIV-1 RNA was quantified in seminal and blood plasma by TaqMan real-time polymerase chain reaction (RT-PCR) or Roche Amplicor Monitor assays. HSV and seminal cytomegalovirus (CMV) were quantified by RT-PCR. Linear mixed models examined differences within participants by treatment arm. RESULTS: Median CD4 cell count of participants was 424 cells/microl. HIV-1 was detected in 71% of 231 semen specimens. HSV was detected from 29 and 4.4% of swabs on placebo and valacyclovir, respectively (P < 0.001). Valacyclovir significantly reduced the proportion of days with detectable seminal HIV-1 (63% during valacyclovir vs. 78% during placebo; P = 0.04). Seminal HIV-1 quantity was 0.25 log10 copies/ml lower [95% confidence interval (CI) -0.40 to -0.10; P = 0.001] during the valacyclovir arm compared with placebo, a 44% reduction. CD4 cell count (P = 0.32) and seminal cellular CMV quantity (P = 0.68) did not predict seminal plasma HIV-1 level. CONCLUSIONS: Suppressive valacyclovir reduced seminal HIV-1 levels in HIV-1/HSV-2 co-infected MSM not receiving ART. The significance of this finding will be evaluated in a trial with HIV-1 transmission as the outcome