Price stickiness and markup variations in market games

In this paper, we show that the Shapley–Shubik market game model with production naturally generates an equilibration mechanism that can accommodate price stickiness arising from strategic interactions of firms. Unlike New Keynesian models that show similar price stickiness results, the market game model does not require enforcing menu costs or other additional restraints on price adjustment mechanisms in order to generate price stickiness. As such, we suggest that the market game model can provide a good micro-foundation for macroeconomic analysis. We then explicitly show the relationship between a typical firm’s markup of price over marginal cost and its market share

Negotiating the transition from adolescence to motherhood: Coping with prenatal and parenting stress in teenage mothers in Mulago hospital, Uganda

<p>Abstract</p> <p>Background</p> <p>Adolescence is a transitional stage from childhood to adulthood that is characterized by physical, physiological, psychosocial and behavioral changes that are influenced to a large extent by the age, culture and socialization of the individual. To explore what adolescent mothers perceive as their struggles during the period of transition from childhood to parenthood (through motherhood) and to describe strategies employed in coping with stress of pregnancy, motherhood and parenthood.</p> <p>Methods</p> <p>Longitudinal qualitative study involving twenty two in-depth interviews and six focus group discussions among pregnant adolescents who were followed from pregnant to delivery, from January 2004 to August 2005. Participant were selected by theoretical sampling and data was analyzed using grounded theory.</p> <p>Results</p> <p>Overall, young adolescents reported more anxiety, loss of self esteem (when they conceived), difficulty in accessing financial, moral and material support from parents or partners and stigmatization by health workers when they sought care from health facilities. Three strategies by which adolescent mothers cope with parenting and pregnancy stress that were described as utilizing opportunities (thriving), accommodating the challenges (bargaining and surviving), or failure (despairing), and varied in the extent to which they enabled adolescents to cope with the stress.</p> <p>Conclusion</p> <p>Adolescents on the transition to motherhood have variable needs and aspirations and utilize different strategies to cope with the stress of pregnancy and parenthood.</p

Genome-wide association study identifies loci associated with liability to alcohol and drug dependence that is associated with variability in reward-related ventral striatum activity in African- and European-Americans.

Genetic influences on alcohol and drug dependence partially overlap, however, specific loci underlying this overlap remain unclear. We conducted a genome-wide association study (GWAS) of a phenotype representing alcohol or illicit drug dependence (ANYDEP) among 7291 European-Americans (EA; 2927 cases) and 3132 African-Americans (AA: 1315 cases) participating in the family-based Collaborative Study on the Genetics of Alcoholism. ANYDEP was heritable (h 2 in EA = 0.60, AA = 0.37). The AA GWAS identified three regions with genome-wide significant (GWS; P &lt; 5E-08) single nucleotide polymorphisms (SNPs) on chromosomes 3 (rs34066662, rs58801820) and 13 (rs75168521, rs78886294), and an insertion-deletion on chromosome 5 (chr5:141988181). No polymorphisms reached GWS in the EA. One GWS region (chromosome 1: rs1890881) emerged from a trans-ancestral meta-analysis (EA + AA) of ANYDEP, and was attributable to alcohol dependence in both samples. Four genes (AA: CRKL, DZIP3, SBK3; EA: P2RX6) and four sets of genes were significantly enriched within biological pathways for hemostasis and signal transduction. GWS signals did not replicate in two independent samples but there was weak evidence for association between rs1890881 and alcohol intake in the UK Biobank. Among 118 AA and 481 EA individuals from the Duke Neurogenetics Study, rs75168521 and rs1890881 genotypes were associated with variability in reward-related ventral striatum activation. This study identified novel loci for substance dependence and provides preliminary evidence that these variants are also associated with individual differences in neural reward reactivity. Gene discovery efforts in non-European samples with distinct patterns of substance use may lead to the identification of novel ancestry-specific genetic markers of risk

Age-dependent effects of low-dose nicotine treatment on cocaine-induced behavioral plasticity in rats

Epidemiological evidence of early adolescent tobacco use, prior to that of marijuana and other illicit drugs, has led to the hypothesis that nicotine is a “gateway” drug that sensitizes reward pathways to the addictive effects of other psychostimulants. To test this hypothesis, we have compared the effect of a brief, low-dose nicotine pretreatment of adolescent and adult rats on subsequent locomotor response to acute and chronic cocaine. Adolescents, aged postnatal day (P) 28, and adults, aged P86, were given four daily injections of saline or nicotine (0.06&nbsp;mg/kg, i.v.). At P32 and P90, rats were given acute injections of cocaine (0, 0.4 or 1.0&nbsp;mg/kg, i.v.) and monitored for locomotor activity in either a habituated or novel test environment. To examine cocaine sensitization, rats were treated for 3&nbsp;days with saline or cocaine (0.4&nbsp;mg/kg, i.v.), and, after 1&nbsp;day of withdrawal, were given a challenge dose of cocaine (0.4&nbsp;mg/kg, i.v.). Nicotine pretreatment did not affect acute, drug-induced locomotor activity at either age. However, age differences in cocaine response were observed, with adolescent animals showing enhanced locomotor activity in the novel environment. Adolescent controls did not exhibit cocaine-induced locomotor sensitization, whereas adults did. Nicotine pretreatment during adolescence promoted the development and expression of a sensitized response to repeated cocaine exposure similar to that observed in saline-pretreated adult controls. These findings show that brief pretreatment with nicotine, in a low dose comparable to that inhaled in 2–4 cigarettes, enhances cocaine-induced behavioral plasticity in adolescent rats

Training in childhood obesity management in the United States: a survey of pediatric, internal medicine-pediatrics and family medicine residency program directors

<p>Abstract</p> <p>Background</p> <p>Information about the availability and effectiveness of childhood obesity training during residency is limited.</p> <p>Methods</p> <p>We surveyed residency program directors from pediatric, internal medicine-pediatrics (IM-Peds), and family medicine residency programs between September 2007 and January 2008 about childhood obesity training offered in their programs.</p> <p>Results</p> <p>The response rate was 42.2% (299/709) and ranged by specialty from 40.1% to 45.4%. Overall, 52.5% of respondents felt that childhood obesity training in residency was extremely important, and the majority of programs offered training in aspects of childhood obesity management including prevention (N = 240, 80.3%), diagnosis (N = 282, 94.3%), diagnosis of complications (N = 249, 83.3%), and treatment (N = 242, 80.9%). However, only 18.1% (N = 54) of programs had a formal childhood obesity curriculum with variability across specialties. Specifically, 35.5% of IM-Peds programs had a formal curriculum compared to only 22.6% of pediatric and 13.9% of family medicine programs (p < 0.01). Didactic instruction was the most commonly used training method but was rated as only somewhat effective by 67.9% of respondents using this method. The most frequently cited significant barrier to implementing childhood obesity training was competing curricular demands (58.5%).</p> <p>Conclusions</p> <p>While most residents receive training in aspects of childhood obesity management, deficits may exist in training quality with a minority of programs offering a formal childhood obesity curriculum. Given the high prevalence of childhood obesity, a greater emphasis should be placed on development and use of effective training strategies suitable for all specialties training physicians to care for children.</p

Community Analysis of Chronic Wound Bacteria Using 16S rRNA Gene-Based Pyrosequencing: Impact of Diabetes and Antibiotics on Chronic Wound Microbiota

Background: Bacterial colonization is hypothesized to play a pathogenic role in the non-healing state of chronic wounds. We characterized wound bacteria from a cohort of chronic wound patients using a 16S rRNA gene-based pyrosequencing approach and assessed the impact of diabetes and antibiotics on chronic wound microbiota. Methodology/Principal Findings: We prospectively enrolled 24 patients at a referral wound center in Baltimore, MD; sampled patients' wounds by curette; cultured samples under aerobic and anaerobic conditions; and pyrosequenced the 16S rRNA V3 hypervariable region. The 16S rRNA gene-based analyses revealed an average of 10 different bacterial families in wounds-approximately 4 times more than estimated by culture-based analyses. Fastidious anaerobic bacteria belonging to the Clostridiales family XI were among the most prevalent bacteria identified exclusively by 16S rRNA gene-based analyses. Community-scale analyses showed that wound microbiota from antibiotic treated patients were significantly different from untreated patients (p = 0.007) and were characterized by increased Pseudomonadaceae abundance. These analyses also revealed that antibiotic use was associated with decreased Streptococcaceae among diabetics and that Streptococcaceae was more abundant among diabetics as compared to non-diabetics. Conclusions/Significance: The 16S rRNA gene-based analyses revealed complex bacterial communities including anaerobic bacteria that may play causative roles in the non-healing state of some chronic wounds. Our data suggest that antimicrobial therapy alters community structure-reducing some bacteria while selecting for others

Does Immediate Breast Reconstruction after Mastectomy affect the Initiation of Adjuvant Chemotherapy?

Purpose: The frequency of immediate breast reconstruction (IBR) is increasing, and the types of reconstruction used are diverse. Adjuvant chemotherapy is a life-saving intervention in selected high-risk breast cancer patients. The aim of our study was to determine how IBR and type of reconstruction affect the timing of the initiation of chemotherapy. Methods: We obtained data from female breast cancer patients treated by mastectomy with IBR (IBR group) and without IBR (mastectomy only group) who received adjuvant chemotherapy between January 1, 2008, and December 31, 2010. We retrospectively collected data including patient characteristics, disease characteristics, treatment details, and treatment outcomes from our institutional electronic patient database and medical treatment records. The reconstruction types were categorized as deep inferior epigastric perforator (DIEP) flap, latissimus dorsi (LD) flap and tissue expander/implant (TEI). Results

New fossils of Australopithecus sediba reveal a nearly complete lower back.

Adaptations of the lower back to bipedalism are frequently discussed but infrequently demonstrated in early fossil hominins. Newly discovered lumbar vertebrae contribute to a near-complete lower back of Malapa Hominin 2 (MH2), offering additional insights into posture and locomotion in Australopithecus sediba. We show that MH2 possessed a lower back consistent with lumbar lordosis and other adaptations to bipedalism, including an increase in the width of intervertebral articular facets from the upper to lower lumbar column ('pyramidal configuration'). These results contrast with some recent work on lordosis in fossil hominins, where MH2 was argued to demonstrate no appreciable lordosis ('hypolordosis') similar to Neandertals. Our three-dimensional geometric morphometric (3D GM) analyses show that MH2's nearly complete middle lumbar vertebra is human-like in overall shape but its vertebral body is somewhat intermediate in shape between modern humans and great apes. Additionally, it bears long, cranially and ventrally oriented costal (transverse) processes, implying powerful trunk musculature. We interpret this combination of features to indicate that A. sediba used its lower back in both bipedal and arboreal positional behaviors, as previously suggested based on multiple lines of evidence from other parts of the skeleton and reconstructed paleobiology of A. sediba

Dealing with heterogeneity of treatment effects: is the literature up to the challenge?

<p>Abstract</p> <p>Background</p> <p>Some patients will experience more or less benefit from treatment than the averages reported from clinical trials; such variation in therapeutic outcome is termed heterogeneity of treatment effects (HTE). Identifying HTE is necessary to individualize treatment. The degree to which heterogeneity is sought and analyzed correctly in the general medical literature is unknown. We undertook this literature sample to track the use of HTE analyses over time, examine the appropriateness of the statistical methods used, and explore the predictors of such analyses.</p> <p>Methods</p> <p>Articles were selected through a probability sample of randomized controlled trials (RCTs) published in <it>Annals of Internal Medicine</it>, <it>BMJ</it>, <it>JAMA</it>, <it>The Lancet</it>, and <it>NEJM </it>during odd numbered months of 1994, 1999, and 2004. RCTs were independently reviewed and coded by two abstractors, with adjudication by a third. Studies were classified as reporting: (1) HTE analysis, utilizing a formal test for heterogeneity or treatment-by-covariate interaction, (2) subgroup analysis only, involving no formal test for heterogeneity or interaction; or (3) neither. Chi-square tests and multiple logistic regression were used to identify variables associated with HTE reporting.</p> <p>Results</p> <p>319 studies were included. Ninety-two (29%) reported HTE analysis; another 88 (28%) reported subgroup analysis only, without examining HTE formally. Major covariates examined included individual risk factors associated with prognosis, responsiveness to treatment, or vulnerability to adverse effects of treatment (56%); gender (30%); age (29%); study site or center (29%); and race/ethnicity (7%). Journal of publication and sample size were significant independent predictors of HTE analysis (p < 0.05 and p < 0.001, respectively).</p> <p>Conclusion</p> <p>HTE is frequently ignored or incorrectly analyzed. An iterative process of exploratory analysis followed by confirmatory HTE analysis will generate the data needed to facilitate an individualized approach to evidence-based medicine.</p

Aggressive fibromatosis of the head and neck: a new classification based on a literature review over 40 years (1968-2008)

BACKGROUND: Fibromatosis is an aggressive fibrous tumor of unknown etiology that is, in some cases, lethal. Until now, there has been no particular classification for the head and neck. Therefore, the aim of the present study was to review the current literature in order to propose a new classification for future studies. METHODS: An evidence-based literature review was conducted from the last 40 years regarding aggressive fibromatosis in the head and neck. Studies that summarized patients' data without including individual data were excluded. RESULTS: Between 1968 and 2008, 179 cases with aggressive fibromatosis of the head and neck were published. The male to female ratio was 91 to 82 with a mean age of 16.87 years, and 57.32% of the described cases that involved the head and neck were found in patients under 11 years. The most common localization was the mandible, followed by the neck. All together, 143 patients were followed up, and in 43 (30.07%), a recurrence was seen. CONCLUSION: No clear prognostic factors for recurrence (age, sex, or localization) were observed. A new classification with regard to hormone receptors and bone involvement could improve the understanding of risk factors and thereby assist in future studies