We consider a general class of first-order nonlinear delay-differential equations (DDEs) with reflectional symmetry, and study completely the bifurcations of the trivial equilibrium under some generic conditions on the Taylor coefficients of the DDE. Our analysis reveals a Hopf bifurcation curve terminating on a pitchfork bifurcation line at a codimension two Takens–Bogdanov point in parameter ...

PURPOSE HIV status is monitored by expression of clinical symptoms as well as CD4 lymphocyte counts. The purpose of this study is to assess the relationship between delayed dental eruption (DDE) and the progression of pediatric HIV infection to AIDS. METHODS A population of 70 perinatally HIV-infected children, aged 5 months to 13 years at their time of entry into the study, received dental e...

Ecotoxicological endpoints based on behavioral traits (e.g., predator avoidance, feeding, and locomotion) may be more sensitive and give more insights into patterns of sublethal toxicity than survivorship tests. In this study, the density-dependent grazing rate of Daphnia pulex pre-exposed to p,p'-dichlorodiphenyldichloroethylene (DDE) (insecticide metabolite) and glyphosate (herbicide), via wa...

Time series analysis with nonlinear delay differential equations (DDEs) reveals nonlinear as well as spectral properties of the underlying dynamical system. Here, global DDE models were used to analyze 5 min data segments of electrocardiographic (ECG) recordings in order to capture distinguishing features for different heart conditions such as normal heart beat, congestive heart failure, and at...

Cooking oil fume (COF) is known to be associated with respiratory diseases and risk of lung cancer. The involvement of Trans, trans-2,4-decadienal (tt-DDE), a major component in COF, is suspected. Male ICR mice were intratracheally instilled with either 8 or 24 mg/kg tt-DDE weekly for eight weeks. Total numbers and types of cells in bronchoalveolar lavage fluids (BAL), as well as pathologic cha...

Polychlorinated biphenyl (PCB) and dichlorodiphenylethane (DDE) methyl sulfone (MSF) metabolites possess high affinities for binding two homologous 16,000 Da homodimeric receptor proteins in the lung (Clara cell secretory protein, CCSP) and the uterus (uteroglobin, UG), leading to selective bioaccumulation of MSFs in these tissues. As marine mammals are highly exposed to organochlorines, concen...

Multivariate methods were used to predict levels of dichlorodiphenyldichloroethene (DDE) and polychlorinated biphenyl (PCB) concentrations in plasma from characteristics that included age, diet, race, reproductive history, socioeconomic status, and reported body mass index (BMI) at several decades of life before blood collection. Measurements were available for organochlorine compound (organoch...

To understand the biokinetics and potential risks of p,p'-dichlorodiphenyltrichloroethane (DDT) and its metabolites, p,p'-dichlorodiphenyldichloroethylene (DDE) and p,p'-dichlorodiphenyldichloroethane (DDD), in fish, we exposed the black sea breams (Acanthopagrus schlegeli) to aqueous and dietary DDTs and then evaluated the bioaccumulation, distribution, biotransformation, and elimination of DD...

We followed 858 children from birth to one year of age to determine whether the presence of polychlorinated biphenyls (PCBs) and dichlorodiphenyl dichloroethene (DDE) in breast milk affected their growth or health. Neither chemical showed an adverse effect on weight or frequency of physician visits for various illnesses, although differences were seen between breast-fed and bottle-fed children,...

One interpretation of the doctrine of double effect (DDE) holds that in situations in which good can be secured for some only if others suffer harm, the pursuit of a good tends to be less acceptable when a resulting harm is intended as a means rather than when it is merely foreseen. The doctrine captures certain moral intuitions about pairs of cases which have the same consequential profiles b...