Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99


Any time

2019 ( 152 )

2018 ( 251 )

2017 ( 247 )

2016 ( 357 )

Custom range...

Search Results: 1 - 10 of 147324 matches for " Roberta B. Ness "
All listed articles are free for downloading (OA Articles)
Page 1 /147324
Display every page Item
Public Health Research Priorities for the Future
Roberta B. Ness
Public Health Reviews , 2011,
Abstract: The last century of innovative public health discoveries has led most of the world’s population to lead longer, healthier lives. Yet, the future holds some of the greatest public health challenges in mankind’s history. Global disparities in health; medication safety; climate change; epidemics of obesity and diabetes; an aging world demographic; and emerging infections all represent problems requiring scientific solutions. The solutions to these problems, like the solutions to those in the last century that contributed so greatly to our quality of life, will require paradigm-shifting innovation.To maximize individual innovative potential, one strategy is formal instruction in the methods of innovative thinking. Teaching innovative thinking is rarely integrated into science training. However 40 years of accumulated evidence suggests that formal instruction results in improved thinking skills. I describe here some of the methods integrated into a course for graduate and professional health science students entitled Innovative Thinking. The curriculum consists of three components: recognizing and finding alternatives to habitual cognitive patterns; learning to use tools that enhance idea generation and originality; and harmonizing divergent thinking with the process of convergent thinking that is central to the scientific method. To build more innovative environments, institutions can promote team science, fund staged scientific designs that are heavy on early prototypes, reward and grow the training programs of past innovators, and become less risk averse.Although public health has accomplished much, it must continue to battle major, growing causes of disease and disability. Innovation is the engine of scientific discovery. Releasing the great potential for discovery in all of us must be central to forwarding health and prosperity in the world.
Cost Comparisons between Home- and Clinic-Based Testing for Sexually Transmitted Diseases in High-Risk Young Women
Kenneth J. Smith,Robert L. Cook,Roberta B. Ness
Infectious Diseases in Obstetrics and Gynecology , 2007, DOI: 10.1155/2007/62467
Abstract: Home testing for chlamydia and gonorrhea increases screening rates, but the cost consequences of this intervention are unclear. We examined the cost differences between home-based and clinic-based testing and the cost-effectiveness of home testing based on the DAISY study, a randomized controlled trial. Direct and indirect costs were estimated for home and clinic testing, and cost-effectiveness was calculated as cost per additional test performed. In the clinic testing group, direct costs were $49/test and indirect costs (the costs of seeking or receiving care) were $62/test. Home testing cost was $25/test. We found that home testing was cost saving when all testing for all patients was considered. However cost savings were not seen when only asymptomatic tests or when patient subgroups were considered. A home testing program could be cost saving, depending on whether changes in clinic testing frequency occur when home testing is available.
Mycoplasma Genitalium Among Women With Nongonococcal, Nonchlamydial Pelvic Inflammatory Disease
Catherine L. Haggerty,Patricia A. Totten,Sabina G. Astete,Roberta B. Ness
Infectious Diseases in Obstetrics and Gynecology , 2006, DOI: 10.1155/idog/2006/30184
Abstract: Pelvic inflammatory disease (PID) is a frequent condition of young women, often resulting in reproductive morbidity. Although Neisseria gonorrhoeae and/or Chlamydia trachomatis are/is recovered from approximately a third to a half of women with PID, the etiologic agent is often unidentified. We need PCR to test for M genitalium among a pilot sample of 50 women with nongonococcal, nonchlamydial endometritis enrolled in the PID evaluation and clinical health (PEACH) study. All participants had pelvic pain, pelvic organ tenderness, and leukorrhea, mucopurulent cervicitis, or untreated cervicitis. Endometritis was defined as ≥5 surface epithelium neutrophils per ×400 field absent of menstrual endometrium and/or ≥2 stromal plasma cells per ×120 field. We detected M genitalium in 7 (14%) of the women tested: 6 (12%) in cervical specimens and 4 (8%) in endometrial specimens. We conclude that M genitalium is prevalent in the endometrium of women with nongonococcal, nonchlamydial PID.
Chlamydia trachomatis Serology in Women with and without Ovarian Cancer
Roberta B. Ness,Caixia Shen,Debra Bass,Carlynn Jackson,Kristen Moysich,Robert Edwards,Robert C. Brunham
Infectious Diseases in Obstetrics and Gynecology , 2008, DOI: 10.1155/2008/219672
Abstract: Pelvic inflammation has been implicated in the genesis of ovarian cancer. We conducted serologic measurements of Chlamydia trachomatis antibodies as a surrogate marker of chlamydial pelvic inflammatory disease. Women with ovarian cancer (=521) and population-based controls (=766) were tested. IgG antibodies to serovar D of chlamydia elementary bodies (EBs) were detected using an ELISA assay. The odds of having ovarian cancer among women with the highest titers (≥0.40 OD units) were 0.6 (95% CI 0.4–0.9). These data do not support our earlier finding of elevated titers for antibodies to C. trachomatis among women with ovarian cancer.
The Role of Chlamydia trachomatis Polymorphic Membrane Proteins in Inflammation and Sequelae among Women with Pelvic Inflammatory Disease
Brandie D. Taylor,Toni Darville,Chun Tan,Patrik M. Bavoil,Roberta B. Ness,Catherine L. Haggerty
Infectious Diseases in Obstetrics and Gynecology , 2011, DOI: 10.1155/2011/989762
Abstract: Chlamydia trachomatis polymorphic membrane proteins (Pmps) may increase genital tract inflammation and play a role in virulence. Antibody levels for PmpA, PmpD, and PmpI, measured in densitometric units, were assessed among a pilot sample of 40 C. trachomatis-infected women with mild-to-moderate clinical PID. Women who expressed antibodies to PmpA were less likely to achieve pregnancy (40.0% versus 85.7%; ) and less likely to have a live birth (0.0% versus 80.0%; ) compared to women who did not express antibody to PmpA. Women who expressed antibodies to PmpI were more likely to have upper genital tract infection (61.5% versus 20.0%; ). However, seropositivity to PmpI and PmpD did not modify the risk of reproductive sequelae or inflammation. Seropositivity to chlamydial PmpA may represent a biomarker of increased risk of sequelae secondary to infection with C. trachomatis. 1. Introduction Chlamydia trachomatis is the most common bacterial sexually transmitted infection in the United States [1]. In women, C. trachomatis can ascend from the endocervix to the upper genital tract and cause pelvic inflammatory disease (PID) and serious reproductive morbidity including infertility and ectopic pregnancy [2]. However, rates of progression vary and 80% or more of women with chlamydia do not develop PID [1]. Some women clear chlamydial infection without tissue damage, while in some cases C. trachomatis induces a chronic low-grade infection [3]. This may lead to persistent inflammation of the upper genital tract causing long-term reproductive sequelae. The pathogenesis of C. trachomatis disease is not well-understood, and pathogen-specific virulence factors that may contribute to variability in the course and outcome of infection have not been identified. Nine surface-exposed C. trachomatis polymorphic membrane proteins (Pmps) are encoded via a multigene family yielding PmpA to PmpI [4]. Pmps represent 13.6% of the coding capacity of the C. trachomatis genome [4], suggesting they have a critical role in biology and virulence [5, 6]. However, the role of Pmps in chlamydial virulence is not well understood. PmpD is a species-common, pan-neutralizing antigen hypothesized to hold potential as a vaccine candidate [6]. Thus, the development of high titers of antibody to PmpD might protect from infection or disease. On the other hand, Chlamydia pneumoniae Pmps have been shown to induce proinflammatory mediators in infected host cells, demonstrating the potential for these proteins to play a direct role in pathogenesis [7, 8]. All nine Pmps are expressed on the surface of
Association of Lower Genital Tract Inflammation With Objective Evidence of Endometritis
Jeffrey F. Peipert,Roberta B. Ness,David E. Soper,Debra Bass
Infectious Diseases in Obstetrics and Gynecology , 2000, DOI: 10.1155/s1064744900000065
Abstract: The purpose of this report is to evaluate the association between lower genital tract inflammation and objectively diagnosed endometritis. We analyzed the first 157 patients enrolled in the PEACH study, a multicenter randomized clinical trial designed to compare the effectiveness of outpatient and inpatient therapy for PID. Women less than 38 years of age, who presented with a history of pelvic discomfort for 30 days or less and who were found to have pelvic organ tenderness (uterine or adnexal tenderness) on bimanual examination, were initially invited to participate. After recruitment of the first 58 patients (group 1) we added the presence of leukorrhea, mucopurulent cervicitis, or untreated positive test for N. gonorrhoeae or C. trachomatis to the inclusion criteria (group 2, N = 99). We compared rates of endometritis in the two groups and calculated the sensitivity, specificity, and predicted values of the presence of white blood cells in the vaginal wet preparation. The rate of upper genital tract infection in group 1 was 46.5% (27/58) compared to 49.5% (49/99) in group 2. Microbiologic evidence of either N. gonorrhoeae or C. trachomatis increased from 22.4% in group 1 to 38.3% in group 2. The presence of Vaginal white blood cells or mueopus has a high sensitivity (88.9%), but a low specificity (19.4%) for the diagnosis of upper genital-tract infection. Assessment of the lower genital tract for evidence of infection or inflammation is a valuable component of the diagnostic evaluation of pelvic inflammatory disease. The presence of either mucopus or vaginal white blood cells is a highly sensitive test for endometritis in patients with pelvic pain and tenderness. Infect. Dis. Obstet. Gynecol. 8:83–87, 2000.
Mycoplasma genitalium among Young, Urban Pregnant Women
Vanessa L. Short,J?rgen S. Jensen,Deborah B. Nelson,Pamela J. Murray,Roberta B. Ness,Catherine L. Haggerty
Infectious Diseases in Obstetrics and Gynecology , 2010, DOI: 10.1155/2010/984760
Abstract: Objective. As the consequences of Mycoplasma genitalium in pregnant women are unknown, we examined the relationship between prenatal M. genitalium infection and SAB. Methods. The presence of M. genitalium was determined by PCR in urine from 82 women who subsequently experienced a SAB and 134 women who maintained their pregnancies past 22 weeks gestation. The relationships between M. genitalium and subsequent SAB, demographic, current pregnancy, and reproductive health history characteristics were evaluated. Results. Compared to women without M. genitalium, women with M. genitalium were more likely to report nulliparity (41.7% versus 17.4%, ), history of pelvic inflammatory disease (27.3% versus 8.8%, ), prior C. trachomatis infection (63.6% versus 36.9%, ) and problems getting pregnant (18.2% versus 4.4%, ). M. genitalium was not associated with SAB (AOR 0.9, 95% CI 0.2–3.8). Conclusions. Pregnant women who test positive for M. genitalium do not have an increased risk of SAB but report a history of reproductive morbidities. 1. Introduction Spontaneous abortion (SAB), the loss of a conceptus prior to 20 weeks, is the most common adverse outcome of pregnancy, occurring in an estimated 15% of clinically recognized pregnancies [1] and up to 50% of all pregnancies [2]. Many SABs occurring in the first trimester are due to phenotypic and/or chromosomal abnormalities, while environmental factors may have a greater impact on SAB occurring in later pregnancy [2]. Evidence suggests that sexually transmitted bacterial and viral infections, such as Treponema pallidum, bacterial vaginosis (BV), and Chlamydia trachomatis, may play a role in SAB [3–13]. Mycoplasma genitalium, a sexually transmitted bacterium, has been linked to various adverse gynecologic and reproductive events. It has been associated with cervicitis [14–17] and has been implicated as an etiological agent of pelvic inflammatory disease (PID) independent of C. trachomatis and Neisseria gonorrhoeae [17–20]. Furthermore, it has been detected in cervical and salpingeal samples from women with laparoscopically confirmed salpingitis [21] and in cervical and endometrial specimens from women with histologically confirmed endometritis [18]. A serologic relationship between M. genitalium and tubal factor infertility has also been identified [22, 23]. Because M. genitalium has been associated with these morbidities, it is plausible that M. genitalium can infect the upper genital tract during pregnancy, resulting in adverse pregnancy outcomes. However, data on M. genitalium in pregnancy are sparse. Whereas two
Throughput of Rateless Codes over Broadcast Erasure Channels
Yang Yang,Ness B. Shroff
Mathematics , 2012,
Abstract: In this paper, we characterize the throughput of a broadcast network with n receivers using rateless codes with block size K. We assume that the underlying channel is a Markov modulated erasure channel that is i.i.d. across users, but can be correlated in time. We characterize the system throughput asymptotically in n. Specifically, we explicitly show how the throughput behaves for different values of the coding block size K as a function of n, as n approaches infinity. For finite values of K and n, under the more restrictive assumption of Gilbert-Elliott channels, we are able to provide a lower bound on the maximum achievable throughput. Using simulations we show the tightness of the bound with respect to system parameters n and K, and find that its performance is significantly better than the previously known lower bounds.
Throughput-optimal Scheduling in Multi-hop Wireless Networks without Per-flow Information
Bo Ji,Changhee Joo,Ness B. Shroff
Mathematics , 2011,
Abstract: In this paper, we consider the problem of link scheduling in multi-hop wireless networks under general interference constraints. Our goal is to design scheduling schemes that do not use per-flow or per-destination information, maintain a single data queue for each link, and exploit only local information, while guaranteeing throughput optimality. Although the celebrated back-pressure algorithm maximizes throughput, it requires per-flow or per-destination information. It is usually difficult to obtain and maintain this type of information, especially in large networks, where there are numerous flows. Also, the back-pressure algorithm maintains a complex data structure at each node, keeps exchanging queue length information among neighboring nodes, and commonly results in poor delay performance. In this paper, we propose scheduling schemes that can circumvent these drawbacks and guarantee throughput optimality. These schemes use either the readily available hop-count information or only the local information for each link. We rigorously analyze the performance of the proposed schemes using fluid limit techniques via an inductive argument and show that they are throughput-optimal. We also conduct simulations to validate our theoretical results in various settings, and show that the proposed schemes can substantially improve the delay performance in most scenarios.
Multiuser Scheduling in a Markov-modeled Downlink using Randomly Delayed ARQ Feedback
Sugumar Murugesan,Philip Schniter,Ness B. Shroff
Mathematics , 2010,
Abstract: We focus on the downlink of a cellular system, which corresponds to the bulk of the data transfer in such wireless systems. We address the problem of opportunistic multiuser scheduling under imperfect channel state information, by exploiting the memory inherent in the channel. In our setting, the channel between the base station and each user is modeled by a two-state Markov chain and the scheduled user sends back an ARQ feedback signal that arrives at the scheduler with a random delay that is i.i.d across users and time. The scheduler indirectly estimates the channel via accumulated delayed-ARQ feedback and uses this information to make scheduling decisions. We formulate a throughput maximization problem as a partially observable Markov decision process (POMDP). For the case of two users in the system, we show that a greedy policy is sum throughput optimal for any distribution on the ARQ feedback delay. For the case of more than two users, we prove that the greedy policy is suboptimal and demonstrate, via numerical studies, that it has near optimal performance. We show that the greedy policy can be implemented by a simple algorithm that does not require the statistics of the underlying Markov channel or the ARQ feedback delay, thus making it robust against errors in system parameter estimation. Establishing an equivalence between the two-user system and a genie-aided system, we obtain a simple closed form expression for the sum capacity of the Markov-modeled downlink. We further derive inner and outer bounds on the capacity region of the Markov-modeled downlink and tighten these bounds for special cases of the system parameters.
Page 1 /147324
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.