Light-adapted spectral sensitivity of the goldfish: A reflex measure

Light-adapted spectral sensitivity of the goldfish was measured using the dorsal light reaction--the reflexive tendency of fish to tilt their dorsal surface toward bright light. Subjects were placed between two 150[deg] extended monochromatic fields, one of which was always 532 nm. The angle of tilt toward or away from the 532 nm light was measured, and the relative intensities of the fields were adjusted until the fish did not tilt. Blind fish did not tilt at all, and fish without utricular otoliths tilted more than normal. The spectral sensitivity obtained using this method peaked near 600 nm and was shallow and broad. The results are similar to those of electrophysiological studies, but different from other behavioral studies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22775/1/0000330.pd

Measuring co-authorship and networking-adjusted scientific impact

Appraisal of the scientific impact of researchers, teams and institutions with productivity and citation metrics has major repercussions. Funding and promotion of individuals and survival of teams and institutions depend on publications and citations. In this competitive environment, the number of authors per paper is increasing and apparently some co-authors don't satisfy authorship criteria. Listing of individual contributions is still sporadic and also open to manipulation. Metrics are needed to measure the networking intensity for a single scientist or group of scientists accounting for patterns of co-authorship. Here, I define I1 for a single scientist as the number of authors who appear in at least I1 papers of the specific scientist. For a group of scientists or institution, In is defined as the number of authors who appear in at least In papers that bear the affiliation of the group or institution. I1 depends on the number of papers authored Np. The power exponent R of the relationship between I1 and Np categorizes scientists as solitary (R>2.5), nuclear (R=2.25-2.5), networked (R=2-2.25), extensively networked (R=1.75-2) or collaborators (R<1.75). R may be used to adjust for co-authorship networking the citation impact of a scientist. In similarly provides a simple measure of the effective networking size to adjust the citation impact of groups or institutions. Empirical data are provided for single scientists and institutions for the proposed metrics. Cautious adoption of adjustments for co-authorship and networking in scientific appraisals may offer incentives for more accountable co-authorship behaviour in published articles.Comment: 25 pages, 5 figure

Estimating the Effect of Depression on HIV Transmission Risk Behaviors Among People Who Inject Drugs in Vietnam: A Causal Approach

The burden of depression and HIV is high among people who inject drugs (PWID), yet the effect of depression on transmission risk behaviors is not well understood in this population. Using causal inference methods, we analyzed data from 455 PWID living with HIV in Vietnam 2009–2013. Study visits every 6 months over 2 years measured depressive symptoms in the past week and injecting and sexual behaviors in the prior 3 months. Severe depressive symptoms (vs. mild/no symptoms) increased injection equipment sharing (risk difference [RD] = 3.9 percentage points, 95% CI −1.7, 9.6) but not condomless sex (RD = −1.8, 95% CI −6.4, 2.8) as reported 6 months later. The cross-sectional association with injection equipment sharing at the same visit (RD = 6.2, 95% CI 1.4, 11.0) was stronger than the longitudinal effect. Interventions on depression among PWID may decrease sharing of injection equipment and the corresponding risk of HIV transmission. Clinical trial registration ClinicalTrials.gov NCT01689545

The role of depression in secondary HIV transmission among people who inject drugs in Vietnam: A mathematical modeling analysis

Background Among people who inject drugs (PWID), depression burden is high and may interfere with HIV prevention efforts. Although depression is known to affect injecting behaviors and HIV treatment, its overall impact on HIV transmission has not been quantified. Using mathematical modeling, we sought to estimate secondary HIV transmissions and identify differences by depression among PWID. Methods We analyzed longitudinal data from 455 PWID living with HIV in Vietnam during 2009–2013. Using a Bernoulli process model with individual-level viral load and behavioral data from baseline and 6-month follow-up visits, we estimated secondary HIV transmission events from participants to their potentially susceptible injecting partners. To evaluate differences by depression, we compared modeled transmissions per 1,000 PWID across depressive symptom categories (severe, mild, or no symptoms) in the three months before each visit. Results We estimated a median of 41.2 (2.5th, 97.5th percentiles: 33.2–49.2) secondary transmissions from all reported acts of sharing injection equipment with 833 injecting partners in the three months before baseline. Nearly half (41%) of modeled transmissions arose from fewer than 5% of participants in that period. Modeled transmissions per 1,000 PWID in that period were highest for severe depressive symptoms (100.4, 80.6–120.2) vs. mild (87.0, 68.2–109.4) or no symptoms (78.9, 63.4–94.1). Transmission estimates fell to near-zero at the 6-month visit. Conclusions Secondary transmissions were predicted to increase with depression severity, although most arose from a small number of participants. Our findings suggest that effective depression interventions could have the important added benefit of reducing HIV transmission among PWID. This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose

Depression, antiretroviral therapy initiation, and HIV viral suppression among people who inject drugs in Vietnam

Background: The burden of depression is high among people who inject drugs (PWID) and may contribute to the spread of HIV through poor treatment engagement and persistent viremia. We estimated the effects of depression on antiretroviral therapy (ART) initiation and viral suppression among PWID living with HIV. Methods: Longitudinal data were collected from 455 PWID living with HIV in Vietnam during 2009–2013. We estimated the 6- and 12-month cumulative incidence of ART initiation and viral suppression, accounting for time-varying confounding, competing events, and missing data. The cumulative incidence difference (CID) contrasted the incidence of each outcome had participants always vs. never experienced severe depressive symptoms across study visits to date. Results: Severe depressive symptoms decreased the cumulative incidence of ART initiation, with CID values comparing always vs. never having severe depressive symptoms of -7.5 percentage points (95% CI: -17.2, 2.2) at 6 months and -7.1 (95% CI: -17.9, 3.7) at 12 months. There was no appreciable difference in the cumulative incidence of viral suppression at 6 months (CID = 0.3, 95% CI: -11.3, 11.9) or 12 months (CID = 2.0, 95% CI: -21.8, 25.8). Limitations: Discrepancies between the ART initiation and viral suppression outcomes could be due to under-reporting of ART use and missing data on viral load. Conclusions: Future work probing the seemingly antagonistic effect of depression on treatment uptake – but not viral suppression – will inform the design of interventions promoting HIV clinical outcomes and reducing onward transmission among PWID

Equilibrium (Zipf) and Dynamic (Grasseberg-Procaccia) method based analyses of human texts. A comparison of natural (english) and artificial (esperanto) languages

A comparison of two english texts from Lewis Carroll, one (Alice in wonderland), also translated into esperanto, the other (Through a looking glass) are discussed in order to observe whether natural and artificial languages significantly differ from each other. One dimensional time series like signals are constructed using only word frequencies (FTS) or word lengths (LTS). The data is studied through (i) a Zipf method for sorting out correlations in the FTS and (ii) a Grassberger-Procaccia (GP) technique based method for finding correlations in LTS. Features are compared : different power laws are observed with characteristic exponents for the ranking properties, and the {\it phase space attractor dimensionality}. The Zipf exponent can take values much less than unity ($ca.$ 0.50 or 0.30) depending on how a sentence is defined. This non-universality is conjectured to be a measure of the author $style$. Moreover the attractor dimension $r$ is a simple function of the so called phase space dimension $n$, i.e., $r = n^{\lambda}$, with $\lambda = 0.79$. Such an exponent should also conjecture to be a measure of the author $creativity$. However, even though there are quantitative differences between the original english text and its esperanto translation, the qualitative differences are very minutes, indicating in this case a translation relatively well respecting, along our analysis lines, the content of the author writing.Comment: 22 pages, 87 references, 5 tables, 8 figure

Modeling the Population-Level Effects of Male Circumcision as an HIV-Preventive Measure: A Gendered Perspective

BACKGROUND: Evidence from biological, epidemiological, and controlled intervention studies has demonstrated that male circumcision (MC) protects males from HIV infection, and MC is now advocated as a public-health intervention against HIV. MC provides direct protection only to men, but is expected to provide indirect protection to women at risk of acquiring HIV from heterosexual transmission. How such indirect protection interacts with the possibility that MC campaigns will lead to behavior changes, however, is not yet well understood. Our objective here is to investigate the link between individual-level effects of MC campaigns and long-term population-level outcomes resulting from disease dynamics, looking at both genders separately, over a broad range of parameters. METHODS AND FINDINGS: We use simple mathematical models of heterosexual transmission to investigate the potential effects of a circumcision scale-up, combined with possible associated behavioral disinhibition. We examine patterns in expected long-term prevalence using a simple equilibrium model based on transmission factors, and validate our results with ODE-based simulations, focusing on the link between effects on females and those on males.We find that the long-term population-level effects on females and males are not strongly linked: there are many possible ways in which an intervention which reduces prevalence in males might nonetheless increase prevalence in females. CONCLUSIONS: Since an intervention that reduces long-term male prevalence could nonetheless increase long-term female prevalence, MC campaigns should explicitly consider both the short-term and long-term effects of MC interventions on females. Our findings strongly underline the importance of pairing MC programs with education, support programs and HIV testing and counseling, together with other prevention measures

Integrated syphilis/HIV screening in China: a qualitative analysis

<p>Abstract</p> <p>Background</p> <p>The last decade has seen enormous advances in HIV treatment and care, but how to implement scaled up HIV testing, prevention, and treatment in low-income areas still presents a formidable public health challenge. South China faces expanding syphilis and sexually transmitted HIV epidemics, but health systems characteristics important for scaling up syphilis and HIV testing have not been defined.</p> <p>Methods</p> <p>A purposive sample to ensure public, private, and public-private hybrid STI clinic inclusion was selected in a South China city. Eight key informant interviews were conducted with the STI clinic manager, followed by eight focus group discussions with physicians. Data collection relied on a semi-structured format that included questions in each of the following domains: 1) clinical facilities; 2) laboratory capacity with a focus on syphilis/HIV diagnosis; 3) clinic personnel; 4) physical space with a focus on locations to disclose confidential results; 5) financial support.</p> <p>Results</p> <p>Public STI clinics had free syphilis testing/treatment and laboratory facilities to perform essential syphilis and HIV tests. However, despite serving a large number of STI patients, private STI clinics lacked nontreponemal syphilis testing, HIV testing, and had fewer connections to the public health infrastructure. Formally trained assistant physicians were 2.5 times as common as physicians at STI clinics. Only one of the 8 sites had onsite voluntary counseling and testing (VCT) services available.</p> <p>Conclusion</p> <p>These STI case studies reveal the potential for expanding integrated syphilis/HIV services at public STI clinics in China. More health services research is needed to guide scale-up of syphilis/HIV testing in China.</p