Alternative Distribution Models Research Articles

Experience of social harms among female sex workers following HIV self-test distribution in Malawi: results of a cohort study

BackgroundIn Malawi, female sex workers (FSW) have high HIV incidence and regular testing is suggested. HIV self-testing (HIVST) is a safe and acceptable alternative to standard testing services. This study assessed; whether social harms were more likely to be reported after HIVST distribution to FSW by peer distributors than after facility-based HIV testing and whether FSW regretted HIVST use or experienced associated relationship problems.MethodsPeer HIVST distributors, who were FSW, were recruited in Blantyre district, Malawi between February and July 2017. Among HIVST recipients a prospective cohort was recruited. Interviews were conducted at baseline and at end-line, 3 months later. Participants completed daily sexual activity diaries. End-line data were analysed using logistic regression to assess whether regret or relationship problems were associated with HIVST use. Sexual activity data were analysed using Generalised Estimating Equations to assess whether HIVST use was temporally associated with an increase in social harms.ResultsOf 265 FSW recruited and offered HIVST, 131 completed both interviews. Of these, 31/131(23.7%) reported initial regret after HIVST use, this reduced to 23/131(17.6%) at the 3-month follow-up. Relationship problems were reported by 12/131(9.2%). Regret about HIVST use was less commonly reported in those aged 26–35 years compared to those aged 16–25 years (OR immediate regret—0.40 95% CI 0.16–1.01) (OR current regret—0.22 95% CI 0.07 – 0.71) and was not associated with the HIVST result. There was limited evidence that reports of verbal abuse perpetrated by clients in the week following HIVST use were greater than when there was no testing in the preceding week. There was no evidence for increases in any other social harms. There was some evidence of coercion to test, most commonly initiated by the peer distributor.ConclusionsLittle evidence was found that the peer distribution model was associated with increased levels of social harms, however programmes aimed at reaching FSW need to carefully consider possible unintended consequences of their service delivery approaches, including the potential for peer distributors to coerce individuals to test or disclose their test results and alternative distribution models may need to be considered.

New Observations on Zipf’s Law in Passwords

As password distribution lays the foundation for various password research, accurately characterizing it receives considerable attention. At IEEE TIFS’17, Wang et al. proposed the CDF-Zipf distribution model with the golden-section-search (GSS) fitting method to find the optimal parameters. Their model has been adopted by over 120 password-related studies. In this paper, we address their remaining, fundamental goodness-of-fit issue of password distribution in a principled approach. First, we prove that the confidence level of the state-of-the-art Monte Carlo approach (MCA, for the goodness-of-fit test) converges asymptotically to 0. By experimenting on 228.92 million real-world passwords, we confirm Wang et al.’s conjecture on the effect of sample size that minor deviations would lead to statistical significance for large-scale datasets. We propose both absolute and relative deviation metrics, and find that 1% random deviations in both metrics suffice to reject CDF-Zipf. Second, we attempt to reduce the non-negligible gap between the empirical and fitted distributions (with the maximum deviation of cumulative distribution function (CDF) being 1.91% on average). We explore eight alternative distribution models in two coordinate systems, and find that three models are more accurate than CDF-Zipf, but none can pass MCA. Particularly, we reveal that stretched-exponential, a variant of CDF-Zipf, can on average reduce the maximum CDF deviation from 1.91% to 1.25%. Third, to replace MCA, we introduce a new goodness-of-fit measure based on log-likelihoods. We find that stretched-exponential constantly has a larger log-likelihood than its counterparts. In all, stretched-exponential fits passwords better and further supports Zipf’s law in passwords.

DMPA-SC stock: Cross-site trends by facility type

ObjectivesTo measure trends in the supply of DMPA-SC in public and private health facilities and compare with other prominent modern methods. Study designWe used repeated cross-sectional data from service-delivery-point surveys in six settings: Burkina Faso, Democratic Republic of Congo (Kinshasa and Kongo Central), Nigeria (Kano and Lagos), and Uganda, each with 3-5 rounds of data collected between 2016 and 2020. We analyzed trends in DMPA-SC availability using percent of service delivery points offering the method and percent experiencing stockouts; trends were compared with those for DMPA-IM, IUD, implants, and other short-acting methods, by facility type. ResultsAll settings showed increased offering of DMPA-SC over time for both private and public facilities. Larger proportions of public facilities provided DMPA-SC compared to private facilities (66%–97% vs 16%–50% by 2019–2020). DMPA-SC was provided by fewer facilities than DMPA-IM (90%–100% public, 34%–69% private by 2019–2020), but comparable to implants (83%–100% public, 15%–52% private by 2019–2020) and IUDs (55%–91% public, 0%–44% private by 2019–2020). Trends of DMPA-SC stock varied by setting, with more consistent stock available in private facilities in the DRC and in public facilities in Burkina Faso and Nigeria. Uganda showed decreasing stock in public facilities but increasing stock in private facilities. ConclusionDMPA-SC availability has been increasing since its introduction in sub-Saharan Africa, yet significant gaps in stock exist. Countries should consider alternative distribution models to address these issues. ImplicationsOur findings may help inform countries about the need to monitor DMPA-SC availability and to consider solutions that ensure contraceptive options are available to women who need them and disruptions to contraceptive use are minimized.

Learning word representation by jointly using neighbor and syntactic contexts

Interpretability is a significant aspect of the distributed word representation learning model. Although the most advanced pretrained models have achieved the best results till date, the interpretability of a pretrained model is difficult to explain clearly. For this reason, based on the interpretability of distributed word embeddings, this paper presents a method of learning word representation using joint context. At present, the existing distributed word representation models for learning word representations usually focus on either neighbor or syntactic context. We argue that it is necessary to simultaneously model both contexts. In particular, the point mutual information obtained by combining the two types of contexts can efficiently express the correlation between the words. We propose two alternative distribution models for learning word representations by employing the neighbor and syntactic contexts via a simple and effective joint learning framework. Furthermore, the proposed models are trained on a public corpus, and the learned representations are evaluated in word analogy, word similarity, and sentence classification tasks. The experimental results demonstrate the potential of the proposed method.

Time series regression model for infectious disease and weather

Time series regression has been developed and long used to evaluate the short-term associations of air pollution and weather with mortality or morbidity of non-infectious diseases. The application of the regression approaches from this tradition to infectious diseases, however, is less well explored and raises some new issues.We discuss and present potential solutions for five issues often arising in such analyses: changes in immune population, strong autocorrelations, a wide range of plausible lag structures and association patterns, seasonality adjustments, and large overdispersion.The potential approaches are illustrated with datasets of cholera cases and rainfall from Bangladesh and influenza and temperature in Tokyo. Though this article focuses on the application of the traditional time series regression to infectious diseases and weather factors, we also briefly introduce alternative approaches, including mathematical modeling, wavelet analysis, and autoregressive integrated moving average (ARIMA) models.Modifications proposed to standard time series regression practice include using sums of past cases as proxies for the immune population, and using the logarithm of lagged disease counts to control autocorrelation due to true contagion, both of which are motivated from “susceptible-infectious-recovered” (SIR) models. The complexity of lag structures and association patterns can often be informed by biological mechanisms and explored by using distributed lag non-linear models. For overdispersed models, alternative distribution models such as quasi-Poisson and negative binomial should be considered. Time series regression can be used to investigate dependence of infectious diseases on weather, but may need modifying to allow for features specific to this context.

Queensland's film culture: the challenges of local film distribution and festival exhibition

Queensland's film sector is currently in the midst of significant change. Organisations at the centre of the state's industry, such as Screen Queensland, have undergone substantial and ongoing changes in the last five years. Other organisations funded by Screen Queensland, such as QPIX, Queensland's only film development centre, have recently closed. The Brisbane International Film Festival has been restructured to become the Brisbane Asia Pacific Film Festival as of 2014. In an uncertain industry currently characterised by limited funding and diminishing support structures, local emerging filmmakers require significant initiatives and a sophisticated understanding of how to best utilise fledgling distribution models as part of a tailored strategy for their content. This essay includes interviews with emerging Brisbane filmmakers who have used a combination of traditional and contemporary approaches to exhibition and distribution thus far in their careers. It argues that for these filmmakers, while film festivals do function as crucial platforms for exposure, in the current digital market they cannot be relied upon as the only platform in securing further mainstream or commercial release. They can, however, be incorporated into an alternative distribution model that shows awareness of the contemporary situation in Australia. The research findings are arguably indicative of the challenges faced by filmmakers statewide, and suggest that further support strategies need to be considered to revive Queensland's film culture and provide immediate support for emerging filmmakers.

The Øie–Tozer model of drug distribution and its suitability for drugs with different pharmacokinetic behavior

Introduction: Drug distribution is a major pharmacokinetic process that affects the time course of drug concentrations in tissues, biological fluids and the resulting pharmacological activities. Drug distribution may follow different pathways and patterns, and is governed by the drug's physicochemical properties and the body's physiology. The classical Øie–Tozer model is frequently used for predicting volume of drug distribution and for pharmacokinetic calculations.Areas covered: In this review, the suitability of the Øie–Tozer model for drugs that exhibit different distribution patterns is critically analyzed and illustrated. The method used is a pharmacokinetic modeling and simulation approach. It is demonstrated that the major limitation of the Øie–Tozer model stems from its focus on the total drug concentrations and not on the active (unbound) concentrations. Moreover, the Øie–Tozer model may be inappropriate for drugs with nonlinear or complex pharmacokinetic behavior, such as biopharmaceuticals, drug conjugates or for drugs incorporated into drug delivery systems. Distribution mechanisms and alternative distribution models for these drugs are discussed.Expert opinion: The Øie–Tozer model can serve for predicting unbound volume of drug distribution for 'classical' small molecular mass drugs with linear pharmacokinetics. However, more detailed mechanism-based distribution models should be used in preclinical and clinical settings for drugs that exhibit more complex pharmacokinetic behavior.

Music and Cyberliberties (review)

Reviewed by: Music and Cyberliberties Gerry Szymanski Music and Cyberliberties. By Patrick Burkart. Middletown, CT: Wesleyan University Press, 2010. [xi, 180 p. ISBN 9780819569172 (hardcover), $70; ISBN 9780819569189 (paperback), $24.95.] Bibliography, index. When incoming freshman arrive at our music libraries and don't even know what in the world to do with a compact disc, much less a cassette or an LP record, is this a sign of the impending apocalypse? In his book Music and Cyberliberties, Patrick Burkart would seem to think that the sorry state of the business today shares some of that eschatology, with the four fiery horsemen played by Sony-BMG, Vivendi-Universal, Warner, and EMI. And it's certainly true; since the turn of the century, the music industry has changed radically in a very short amount of time. With the introduction of the Apple's iTunes online store, more music is now being purchased digitally through a computer than physically on such traditional media as the compact disc. But in framing the struggle between the powerful conglomerate labels that have sorted out in the music recording industry and altruistic individual musicians or bands, Burkart adds an element of melodrama with his use of arduous sociological lingo that almost pushes the tone into gimcrackery. As such, this book explores the ontology of normative lifeworlds through the theory of communicative action, and does not do it in the everyday language of the musician, or even music scholar. From the first pages of the extensive introduction (and the list of over seventy abbreviated acronyms), the audience of the book would appear to be the professional sociologist or doctor of philosophy, not the undergraduate music student looking for a source for that bygone, half-forgotten Napster, or even a graduate student wrestling with digital rights management issues. Both topics are featured at length in Music and Cyberliberties, with the history of the rise and fall of the file-sharing site Napster marked as a "watershed" in cyberlibertarianism. This struggle between the user-driven "darknet" site and the Recording Industry Association of America (RIAA) is described in well-written prose and a fairly straightforward manner before the reader is confronted by a sentence such as "So far, incursions from the music lifeworld into the system have not institutionalized into anything like reverse colonization, reverse juridification or decommodification" (pp. 87-88). Is my OED handy? [End Page 555] The situation since the fall of Napster and the realization by the industry that something had to be done in the digital realm leads into a intense discussion of what was to be the next golden age of music, the so-called "Celestial Jukebox"—a phrase defined in a note to the introduction as "the actual or envisioned technology and policy regime that accommodates the media business model of the 'pay-per society' " (p. 143). The origin of this phrase would appear to be a book authored in 1989 by Vincent Mosco called The Pay-Per Society: Computers and Communication in the Information Age: Essays in Critical Theory (Norwood, NJ: Ablex). The crux of Burkart's book, then, is the resistance of the performing musician and the members of the general populace to the attempt on the part of the "big four" music corporate entities mentioned above, along with their legal arm, the RIAA, to force the "Celestial Jukebox" onto the "lifeworld." The social and cultural responses in which the struggle manifests itself are hacking, .mp3 file-sharing and alternative distribution models which try to "stick it to the man." While the somewhat painful shift from mostly physical to mostly digital music in this last decade is all very important and quite relevant, the presentation of these important issues, using the complex philosophical jargon of Jürgen Habermas from Theodore Adorno's Frankfurt school of social theory, makes for a very tough read. Perhaps it is indeed a titanic war between the autocratic recording companies and the heroic hoarder of music who can't just pop a compact disc into a player, but now needs "authentication" from a Web site. Perhaps, also, "virtual communities reproduce systematically distorted communications by being organized in hierarchical administrative-bureaucratic power relationships" (p. 80). Perhaps, indeed...

Report of the ASHP Task Force on Caring for Patients Served by Specialty Suppliers

Task Force recommendations are discussed in more detail in eAppendix A (available at www.ajhp.org). What follows is a brief summary of those recommendations. In very abbreviated terms, the Task Force suggested that ASHP: 1. Consider creating and maintaining a Web resource center on ASHP's website to provide information about restricted drug distributions systems (RDDSs), risk evaluation and mitigation strategies (REMSs), risk assessment and minimization plans (RiskMAPs), and specialty suppliers and products. 2. Provide comprehensive education to members, other health professionals, regulators, third-party payers, patients, and other stakeholders about RDDSs, REMSs, RiskMAPs, and specialty suppliers and products. 3. Develop policies to advocate that a. Pharmacists serve as the institutional leaders in compliance and utilization challenges of safely managing externally supplied medications and related drug administration devices, b. Agencies, organizations, and associations that influence the distribution, sale, and dispensing of medications under these alternative distribution models address issues these models create in continuity of care, reimbursement, and patient safety, c. The Centers for Medicare and Medicaid Services and the Joint Commission develop standards and interpretations that accommodate hospital use of these products and devices when currently available technology (e.g., cold-chain storage, e-pedigree) is used to ensure patient safety, d. Group purchasing organizations negotiate contractual arrangements for specialty pharmaceuticals for both acquisition costs and distribution arrangements, and e. Information technology (IT) be used to resolve issues created by alternative distribution models and that ASHP work with IT vendors to ensure that programs are designed to meet the needs of these evolving models. 4. Quantify through research, perhaps in cooperation with entities such as the Agency for Healthcare Research and Quality, the Institute of Medicine, and the Institute for Safe Medication Practices, the impact of alternative distribution models on financial, safety, clinical, and humanistic patient outcomes. 5. Develop multidisciplinary tools and best practices that assist health care practitioners address the challenges created by alternative distribution models, from patient intake and referral to hospital discharge.

Diversification Meltdown or Just Fat Tails?

An increase in correlation during turbulent market conditions implies a reduction in the benefits arising from portfolio diversification. Unfortunately, it is exactly then that these benefits are most needed. We investigate the robustness of recent empirical results that indicate correlation breakdown by deriving theoretical truncated and exceedance correlations using alternative distributional assumptions. Analytical results show that the empirical meltdown in diversification could be a result of assuming conditional normally distributed returns. When assuming a popular alternative distribution model - the bivariate Student-t distribution - we find significantly less support for diversification meltdown.

HIA—focused on positive results

HIA—focused on positive results

Submicrosecond phospholipid dynamics using a long-lived fluorescence emission anisotropy probe

The use of the long-lived fluorescence probe coronene (mean value of tau(FL) approximately 200 ns) is described for investigating submicrosecond lipid dynamics in DPPC model bilayer systems occurring below the lipid phase transition. Time-resolved fluorescence emission anisotropy decay profiles, measures as a function of increasing temperature toward the lipid-phase transition temperature (T(C)), for coronene-labeled DPPC small unilamellar vesicles (SUVs), are best described in most cases by three rotational decay components (phi(i = 3)). We have interpreted these data using two dynamic lipid bilayer models. In the first, a compartmental model, the long correlation time (phi(N)) is assigned to immobilized coronene molecules located in "gel-like" or highly ordered lipid phases (S-->1) of the bilayer, whereas a second fast rotational time (phi(F) approximately 2-5 ns) is associated with probes residing in more "fluid-like" regions (with corresponding lower ordering, S-->0). Interests here have focused on the origins of an intermediate correlation time (50-100 ns), the associated amplitude (beta(G)) of which increases with increasing temperature. Such behavior suggests a changing rotational environment surrounding the coronene molecules, arising from fluidization of gel lipid. The observed effective correlation time (phi(EFF)) thus reflects a discrete gel-fluid lipid exchange rate (k(FG)). A refinement of the compartmental model invokes a distribution of gel-fluid exchange rates (d(S,T)) corresponding to a distribution of lipid order parameters and is based on an adapted Landau expression for describing "gated" packing fluctuations. A total of seven parameters (five thermodynamic quantities, defined by the free energy versus temperature expansion; one gating parameter (gamma) defining a cooperative "melting" requirement; one limiting diffusion rate (or frequency factor: d(infinity))) suffice to predict complete anisotropy decay curves measured for coronene at several temperatures below the phospholipid T(C). The thermodynamic quantities are associated with the particular lipid of interest (in this case DPPC) and have been determined previously from ultrasound studies, thus representing fixed constants. Hence resolved variables are r(O), temperature-dependent gate parameters (gamma), and limiting diffusion rates (d(infinity)). This alternative distribution model is attractive because it provides a general probe-independent expression for distributed lipid fluctuation-induced probe rotational rates occurring within bilayer membranes below the phospholipid phase transition on the submicrosecond time scale.

Suspended Sediment Concentration Profiles

An evaluation is given of the methods of modeling concentration profiles of suspended non-cohesive sediments in natural streams and under waves. The bottom boundary condition and the distribution models are treated separately. The merits of the simple concentration boundary condition, which has been favored by practice, are compared to those of the more general pickup function approach. Experimental evidence is presented for the inadequacy of pure gradient diffusion as a framework for modeling sediment suspension in streams and under waves. But problems arise when a significant part of the upward sediment flux is carried by vortices through distances comparable with the overall vertical scale. The performance of an alternative distribution model is discussed.

Differences between foreign exchange rate regimes: The view from the tails

In the literature on the empirical unconditional distribution of foreign exchange rate returns there is indication that the type of distribution function is related to the form of exchange rate regime. The analysis has been hampered by the nonnestedness of alternative distribution models. The paper investigates the issue by means of extremal analysis which allows for a unified treatment. In particular, we try to sort out whether apparent distributional differences are due to differences in techniques or in regimes. (JEL F31, F33)