2,412 research outputs found
On the Leading Edge of Innovation: A Comparative Study of Innovation Practices
Susan J. Harper, PhD, is president of Synergy Consulting LLC, Chicago, IL 60646-6036.
Selwyn W. Becker, PhD, is professor emeritus, University of Chicago Graduate School of Business, Chicago, IL 30458
Multi-Scale Entropy Analysis as a Method for Time-Series Analysis of Climate Data
Evidence is mounting that the temporal dynamics of the climate system are changing at the same time as the average global temperature is increasing due to multiple climate forcings. A large number of extreme weather events such as prolonged cold spells, heatwaves, droughts and floods have been recorded around the world in the past 10 years. Such changes in the temporal scaling behaviour of climate time-series data can be difficult to detect. While there are easy and direct ways of analysing climate data by calculating the means and variances for different levels of temporal aggregation, these methods can miss more subtle changes in their dynamics. This paper describes multi-scale entropy (MSE) analysis as a tool to study climate time-series data and to identify temporal scales of variability and their change over time in climate time-series. MSE estimates the sample entropy of the time-series after coarse-graining at different temporal scales. An application of MSE to Central European, variance-adjusted, mean monthly air temperature anomalies (CRUTEM4v) is provided. The results show that the temporal scales of the current climate (1960ā2014) are different from the long-term average (1850ā1960). For temporal scale factors longer than 12 months, the sample entropy increased markedly compared to the long-term record. Such an increase can be explained by systems theory with greater complexity in the regional temperature data. From 1961 the patterns of monthly air temperatures are less regular at time-scales greater than 12 months than in the earlier time period. This finding suggests that, at these inter-annual time scales, the temperature variability has become less predictable than in the past. It is possible that climate system feedbacks are expressed in altered temporal scales of the European temperature time-series data. A comparison with the variance and Shannon entropy shows that MSE analysis can provide additional information on the statistical properties of climate time-series data that can go undetected using traditional method
Predictors of incident herpes simplex virus type 2 infections in young women at risk for unintended pregnancy in San Francisco.
BackgroundYoung women receiving family planning services are at risk for both unintended pregnancy and herpes simplex virus type 2 (HSV-2) infection.MethodsWe performed a secondary analysis using data from a previously published randomized controlled trial evaluating access to emergency contraception on reproductive health outcomes. Women aged 15 to 24 years were recruited from two Planned Parenthood clinics and two community health clinics in San Francisco. Demographic information and sexual history were obtained by interview. HSV-2 seropositivity was determined by fingerstick blood test. New pregnancies were measured by self-report, urine testing and medical chart review. Subjects were evaluated for incident HSV-2 infection and pregnancy at a 6-month follow-up appointment. Women who were pregnant or intending to become pregnant at enrolment were excluded.ResultsAt enrolment 2,104 women were screened for HSV-2 and 170 (8.1%) were seropositive. Eighty-seven percent of initially seronegative women completed the study (n = 1,672) and 73 (4.4%) became HSV-2 seropositive. HSV-2 seroincidence was 7.8 cases per 100 person-years. One hundred and seventeen women (7%) became pregnant and 7 (6%) of these had a seroincident HSV-2 infection during the study. After adjustment for confounders, predictors of incident HSV-2 infection were African American race and having multiple partners in the last six months. Condom use at last sexual encounter was protective.ConclusionHSV-2 seroincidence and the unintended pregnancy rate in young women were high. Providers who counsel women on contraceptive services and sexually transmitted infection prevention could play an expanded role in counselling women about HSV-2 prevention given the potential sequelae in pregnancy. The potential benefit of targeted screening and future vaccination against HSV-2 needs to be assessed in this population
Cisplatin-resistant triple-negative breast cancer subtypes: multiple mechanisms of resistance.
BACKGROUND: Understanding mechanisms underlying specific chemotherapeutic responses in subtypes of cancer may improve identification of treatment strategies most likely to benefit particular patients. For example, triple-negative breast cancer (TNBC) patients have variable response to the chemotherapeutic agent cisplatin. Understanding the basis of treatment response in cancer subtypes will lead to more informed decisions about selection of treatment strategies.
METHODS: In this study we used an integrative functional genomics approach to investigate the molecular mechanisms underlying known cisplatin-response differences among subtypes of TNBC. To identify changes in gene expression that could explain mechanisms of resistance, we examined 102 evolutionarily conserved cisplatin-associated genes, evaluating their differential expression in the cisplatin-sensitive, basal-like 1 (BL1) and basal-like 2 (BL2) subtypes, and the two cisplatin-resistant, luminal androgen receptor (LAR) and mesenchymal (M) subtypes of TNBC.
RESULTS: We found 20 genes that were differentially expressed in at least one subtype. Fifteen of the 20 genes are associated with cell death and are distributed among all TNBC subtypes. The less cisplatin-responsive LAR and M TNBC subtypes show different regulation of 13 genes compared to the more sensitive BL1 and BL2 subtypes. These 13 genes identify a variety of cisplatin-resistance mechanisms including increased transport and detoxification of cisplatin, and mis-regulation of the epithelial to mesenchymal transition.
CONCLUSIONS: We identified gene signatures in resistant TNBC subtypes indicative of mechanisms of cisplatin. Our results indicate that response to cisplatin in TNBC has a complex foundation based on impact of treatment on distinct cellular pathways. We find that examination of expression data in the context of heterogeneous data such as drug-gene interactions leads to a better understanding of mechanisms at work in cancer therapy response
Fenced and fragmented : conservation value of managed metapopulations
Population fragmentation is threatening biodiversity worldwide. Species that once roamed
vast areas are increasingly being conserved in small, isolated areas. Modern management
approaches must adapt to ensure the continued survival and conservation value of these
populations. In South Africa, a managed metapopulation approach has been adopted for
several large carnivore species, all protected in isolated, relatively small, reserves that are
fenced. As far as possible these approaches are based on natural metapopulation structures.
In this network, over the past 25 years, African lions (Panthera leo) were reintroduced
into 44 fenced reserves with little attention given to maintaining genetic diversity. To examine
the situation, we investigated the current genetic provenance and diversity of these
lions. We found that overall genetic diversity was similar to that in a large national park, and
included a mixture of four different southern African evolutionarily significant units (ESUs).
This mixing of ESUs, while not ideal, provides a unique opportunity to study the impact of
mixing ESUs over the long term. We propose a strategic managed metapopulation plan to
ensure the maintenance of genetic diversity and improve the long-term conservation value
of these lions. This managed metapopulation approach could be applied to other species
under similar ecological constraints around the globe.Funding was provided, in part, by Boras
Zoo, Sweden, and Ree Park, Denmark (with
assistance from Frank Oberwemmer and Jesper
Stagegaard). SMM was supported by a Tshwane
University of Technology Doctoral Scholarship.http://www.plosone.orgam201
Evaluation of microsatellite markers for populations studies and forensic identification of African lions (Panthera leo)
The South African lion (Panthera leo) population is highly fragmented. One third of its wild lions
occur in small (<1000 km2) reserves. These lions were reintroduced from other areas of the
speciesā historical range. Management practices on these reserves have not prioritised genetic
provenance or heterozygosity. These trends potentially constrain the conservation value of
these lions. To ensure the best management and long-term survival of these subpopulations as
a viable collective population, the provenance and current genetic diversity must be described.
Concurrently, poaching of lions to supply a growing market for lion bones in Asia may become a
serious conservation challenge in the future. Having a standardised, validated method for
matching confiscated lion parts with carcasses will be a key tool in investigating these crimes. We evaluated 28 microsatellites in the African lion using samples from 18 small reserves and
one captive facility in South Africa, two conservancies in Zimbabwe, and Kruger National and
Kgalagadi Transfrontier Parks to determine the loci most suited for population management
and forensic genetic applications. Twelve microsatellite loci with a match probability of 1.1 x 10-
5 between siblings were identified for forensics. A further ten could be added for population
genetics studies.Jesper Stagegaard and Frank Oberwemmer of the African Lion Interest Group in Europehttp://jhered.oxfordjournals.org2015-11-30hb201
Fenced and fragmented : conservation value of managed metapopulations
Population fragmentation is threatening biodiversity worldwide. Species that once roamed
vast areas are increasingly being conserved in small, isolated areas. Modern management
approaches must adapt to ensure the continued survival and conservation value of these
populations. In South Africa, a managed metapopulation approach has been adopted for
several large carnivore species, all protected in isolated, relatively small, reserves that are
fenced. As far as possible these approaches are based on natural metapopulation structures.
In this network, over the past 25 years, African lions (Panthera leo) were reintroduced
into 44 fenced reserves with little attention given to maintaining genetic diversity. To examine
the situation, we investigated the current genetic provenance and diversity of these
lions. We found that overall genetic diversity was similar to that in a large national park, and
included a mixture of four different southern African evolutionarily significant units (ESUs).
This mixing of ESUs, while not ideal, provides a unique opportunity to study the impact of
mixing ESUs over the long term. We propose a strategic managed metapopulation plan to
ensure the maintenance of genetic diversity and improve the long-term conservation value
of these lions. This managed metapopulation approach could be applied to other species
under similar ecological constraints around the globe.Funding was provided, in part, by Boras
Zoo, Sweden, and Ree Park, Denmark (with
assistance from Frank Oberwemmer and Jesper
Stagegaard). SMM was supported by a Tshwane
University of Technology Doctoral Scholarship.http://www.plosone.orgam201
Carpenter-Coustan Compared With National Diabetes Data Group Criteria for Diagnosing Gestational Diabetes
Use of Carpenter-Coustan compared to National Diabetes Data Group (NDDG) criteria increases the number of women diagnosed with GDM by 30-50%, but whether treatment of this milder GDM reduces adverse outcomes is unknown. We explored the effects of the diagnostic criteria used on the benefits of GDM treatment
Haptoglobin Phenotype, Preeclampsia Risk and the Efficacy of Vitamin C and E Supplementation to Prevent Preeclampsia in a Racially Diverse Population
Haptoglobin's (Hp) antioxidant and pro-angiogenic properties differ between the 1-1, 2-1, and 2-2 phenotypes. Hp phenotype affects cardiovascular disease risk and treatment response to antioxidant vitamins in some non-pregnant populations. We previously demonstrated that preeclampsia risk was doubled in white Hp 2-1 women, compared to Hp 1-1 women. Our objectives were to determine whether we could reproduce this finding in a larger cohort, and to determine whether Hp phenotype influences lack of efficacy of antioxidant vitamins in preventing preeclampsia and serious complications of pregnancy-associated hypertension (PAH). This is a secondary analysis of a randomized controlled trial in which 10,154 low-risk women received daily vitamin C and E, or placebo, from 9-16 weeks gestation until delivery. Hp phenotype was determined in the study prediction cohort (n = 2,393) and a case-control cohort (703 cases, 1,406 controls). The primary outcome was severe PAH, or mild or severe PAH with elevated liver enzymes, elevated serum creatinine, thrombocytopenia, eclampsia, fetal growth restriction, medically indicated preterm birth or perinatal death. Preeclampsia was a secondary outcome. Odds ratios were estimated by logistic regression. Sampling weights were used to reduce bias from an overrepresentation of women with preeclampsia or the primary outcome. There was no relationship between Hp phenotype and the primary outcome or preeclampsia in Hispanic, white/other or black women. Vitamin supplementation did not reduce the risk of the primary outcome or preeclampsia in women of any phenotype. Supplementation increased preeclampsia risk (odds ratio 3.30; 95% confidence interval 1.61-6.82, p<0.01) in Hispanic Hp 2-2 women. Hp phenotype does not influence preeclampsia risk, or identify a subset of women who may benefit from vitamin C and E supplementation to prevent preeclampsia
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