The Relationship between Age at First Birth and Mother's Lifetime Earnings: Evidence from Danish Data

Background

Having children creates career interruptions and reductions in labor income for women. This study documents the relation between the age at first birth (AFB) and women’s labor income. We study these dynamics in the short run (i.e. ratio between labor income at AFB and two years prior to AFB) and long run (i.e., positive/negative differences in total lifetime labor income).

Methods

Using unique Danish administrative register data for the entire Danish population, we estimate the age-income profiles separately for college and non-college women conditional on marital status, and mothers’ age at first birth (AFB). We compute the lifetime labor income differentials by taking the differences between the labor income of women with and without children at each AFB.

Results

The short-run loss in labor income, defined as the difference in percentages between the income earned two years prior to AFB and income earned at AFB, ranges from 37% to 65% for college women and from 40% to 53% for non-college women. These losses decrease monotonically with respect to AFB for both education groups. Our results on the lifetime labor income differentials between mothers and women without children also show a net effect that is monotonic (from negative to positive) in AFB. With AFB<25, the lifetime labor income loss for college women is -204% of their average annual labor income and this figure is -252% for non-college women. There are lifetime labor income gains with AFB>31. The largest gains for college women are 13% of their average annual income and this figure is 50% for non-college women.

Conclusion

Women have a large and unambiguous short-run reduction in labor income at their AFB. In terms of lifetime labor income, both college and non-college women, compared to childless women, are associated with lower income of more than twice their respective average annual income when bearing a child at AFB<25. In other words, women with AFB<25 are associated with a lower lifetime income of more than two years of annual labor income. The lifetime labor incomes for college and non-college women associated with AFB>31 are relatively higher.     

Late toxicity for prostate cancer patients treated with hypofractionated helical tomotherapy

AimThe purpose of this study is to evaluate the long term tolerability of hypofractionated helical tomotherapy (HT) in localized prostate cancer patients.BackgroundPrevious hypofractionated schedules with conventional RT were associated with excessive toxicity, likely due to inadequate sophistication of treatment delivery. There are few data about late toxicity after HT.Materials and methodsWe evaluated 38 patients with primary adenocarcinoma of the prostate. There were 9 (24%), 15 (39%), and 14 (37%) patients with high, intermediate, and low risk, respectively. Patients were treated with hypofractionated HT from May 2008 to February 2011. Hypofractionation regimens included: 68.04 Gy at 2.52 Gy/fraction (N = 25; 66%), 70 Gy at 2.5 Gy/fraction (N = 4; 11%) and 70.2 Gy at 2.6 Gy/fraction (N = 9; 23%). Late genitourinary (GU) and gastrointestinal (GI) toxicity was scored using the Radiation Therapy Oncology Group scoring system.ResultsMedian age at diagnosis was 70 years (range 49–80) and median follow-up, 5.8 years. Late grade 1, 2 and 3 GI toxicity were 13%, 24%, and 2.6%, respectively. Late grade 1, 2, 3 GU toxicity were 29%, 21%, and 8%, respectively. Sexual toxicity was evaluated in 19 patients to be grade 1, 2 in 11% and grade 3 in 16%. Multivariate analysis showed that patients with higher values of rectum V50 associated with late GI toxicity (P = 0.025). Patients with PSA ≤8 (P = 0.048) or comorbidities (P = 0.013) at diagnosis were associated with higher late GU toxicity. Additionally, PSA ≤8 also associated with moderate (grade ≥2) late GU toxicity in the multivariate analysis (P = 0.028).ConclusionsHypofractionated HT can be delivered safely with limited rates of moderate and severe late toxicity. The proportion of the rectum that receives a moderate and high dose, having comorbidities, and PSA at diagnosis seem to associate with long term toxicity.     

Mutational analysis of cytochrome b at the ubiquinol oxidation site of yeast complex III

The cytochrome bc1 complex is a dimeric enzyme of the inner mitochondrial membrane that links electron transfer from ubiquinol to cytochrome c by a protonmotive Q cycle mechanism in which ubiquinol is oxidized at one center in the enzyme, referred to as center P, and ubiquinone is rereduced at a second center, referred to as center N. To better understand the mechanism of ubiquinol oxidation, we have examined catalytic activities and pre-steady-state reduction kinetics of yeast cytochrome bc1 complexes with mutations in cytochrome b that we expected would affect oxidation of ubiquinol. We mutated two residues thought to be involved in proton conduction linked to ubiquinol oxidation, Tyr132 and Glu272, and two residues proposed to be involved in docking ubiquinol into the center P pocket, Phe129 and Tyr279. Substitution of Phe129 by lysine or arginine yielded a respiration-deficient phenotype and lipid-dependent catalytic activity. Increased bypass reactions were detectable for both variants, with F129K showing the more severe effects. Substitution with lysine leads to a disturbed coordination of a b heme as deduced from changes in the midpoint potential and the EPR signature. Removal of the aromatic side chain in position Tyr279 lowers the catalytic activity accompanied by a low level of bypass reactions. Pre-steady-state kinetics of the enzymes modified at Glu272 and Tyr132 confirmed the importance of their functional groups for electron transfer. Altered center N kinetics and activation of ubiquinol oxidation by binding of cytochrome c in the Y132F and E272D enzymes indicate long range effects of these mutations.     

High throughput method for the determination of organochlorine pesticides and polychlorinated biphenyls in human serum

An improved method for the determination of selected organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human serum was developed. The method requires low volume of serum (500 microl) and 48-96 samples per day can be prepared by one analyst without special automatic equipment. Initial extraction was performed using 96-well solid-phase extraction disk plates and was followed by a clean-up with silica gel/sulfuric acid. Different denaturation, elution and clean-up conditions were tested. Quantification was carried out by gas chromatography equipped with electron capture detector (GC-ECD) or mass spectrometer (GC-MS). Recoveries of PCB congeners 28, 52, 101, 118, 138, 153 and 180 and OCPs HCB, beta-HCH, p,p'-DDE and p,p'-DDT at two spiking levels (n=8) varied from 57 to 120%, and intra-day relative standard deviation from 1 to 11%, both depending on spiking level and compound. Inter-day relative standard deviation was <15% in all cases. Limit of quantification (LOQ) for these PCBs ranged from 0.08 to 0.13 ng/ml and for these OCPs from 0.16 to 0.40 ng/ml. The optimized method was applied to the analysis of 1000 serum samples from different places of Spain.     

Formulation matters! A spectroscopic and molecular dynamics investigation on the peptide CIGB552 as itself and in its therapeutical formulation

Synthetic therapeutic peptides (STP) are intensively studied as new-generation drugs, characterized by high purity, biocompatibility, selectivity and stereochemical control. However, most of the studies are focussed on the bioactivity of STP without considering how the formulation actually used for therapy administration could alter the physico-chemical properties of the active principle. The aggregation properties of a 20-mer STP (Ac-His-Ala-Arg-Ile-Lys-D-Pro-Thr-Phe-Arg-Arg-D-Leu-Lys-Trp-Lys-Tyr-Lys-Gly-Lys-Phe-Trp-NH₂), showing antitumor activity, were investigated by optical spectroscopy and atomic force microscopy imaging, as itself (CIGB552) and in its therapeutic formulation (CIGB552TF). It has found that the therapeutic formulation deeply affects the aggregation properties of the investigated peptide and the morphology of the aggregates formed on mica by deposition of CIGB552 and CIGB552TF millimolar solutions. Molecular dynamics simulations studied the first steps of CIGB552 aggregation under physiological ionic strength conditions (NaCl 150 mM), showing that peptide oligomers, from dimers to tetramers, are preferentially formed in this environment. Interestingly, cell viability assays performed on H-460 cell lines indicate a major antiproliferative activity of the peptide in its therapeutic formulation with respect to the peptide aqueous solution.     

Removal of adult cyathostomins alters faecal microbiota and promotes an inflammatory phenotype in horses

The interactions between parasitic helminths and gut microbiota are considered to be an important, although as yet incompletely understood, factor in the regulation of immunity, inflammation and a range of diseases. Infection with intestinal helminths is ubiquitous in grazing horses, with cyathostomins (about 50 species of which are recorded) predominating. Consequences of infection include both chronic effects, and an acute inflammatory syndrome, acute larval cyathostominosis, which sometimes follows removal of adult helminths by administration of anthelmintic drugs. The presence of cyathostomins as a resident helminth population of the equine gut (the “helminthome”) provides an opportunity to investigate the effect helminth infection, and its perturbation, has on both the immune system and bacterial microbiome of the gut, as well as to determine the specific mechanisms of pathophysiology involved in equine acute larval cyathostominosis. We studied changes in the faecal microbiota of two groups of horses following treatment with anthelmintics (fenbendazole or moxidectin). We found decreases in both alpha diversity and beta diversity of the faecal microbiota at Day 7 post-treatment, which were reversed by Day 14. These changes were accompanied by increases in inflammatory biomarkers. The general pattern of faecal microbiota detected was similar to that seen in the relatively few equine gut microbiome studies reported to date. We conclude that interplay between resident cyathostomin populations and the bacterial microbiota of the equine large intestine is important in maintaining homeostasis and that disturbance of this ecology can lead to gut dysbiosis and play a role in the aetiology of inflammatory conditions in the horse, including acute larval cyathostominosis.     

Black flower coloration in wild Lisianthius nigrescens: its chemistry and ecological consequences

The major pigments responsible for the flower color within the black flowered Gentianaceae, Lisianthius nigrescens, were characterized by HPLC and chemical analyses HPLC analysis showed one major and one minor anthocyanin and 3 major and 3 minor flavone glycosides. The anthocyanins [delphinidin-3-O-rhamnol(1-6)galactoside and its 5-O-glucoside] comprised an extraordinary 24% of the dry weight of wild collected L. nigrescens corallas, and were accompanied in a 1:1 ratio by a range of apigenin and luteolin 8-C-glucosides and their 7-O-methyl ethers. The high levels of anthocyanins and flavones (and their co-pigmentation) is thought to account for the almost complete absorption of both UV and visible wavebands observed by reflectance photography.     

Mapping the spatial distribution of plant diversity indices in a tropical forest using multi-spectral satellite image classification and field measurements

The relationships among alpha and beta diversity indices, computed from 141 randomly sampled quadrats, and the vegetation classes obtained by multi-spectral satellite image classification, were used as a strategy for mapping plant diversity in a tropical landscape mosaic. A relatively high accuracy of the land cover map was revealed by the overall accuracy assessment and the Cohen's Kappa statistic. Species accumulation models were used to evaluate how representative the sample size was the different vegetation types. A standard one-way, between-subjects ANOVA confirmed a significant reduction of the within-class variance of plant diversity with respect to their total variance across the landscape. Computed uniformity indices, to assess the internal uniformity of vegetation classes on the diversity indices, confirmed the goodness of the mapped classes in stratifying variability of plant diversity. This allowed for the use of the mapped classes as spatial interpolators of plant diversity values for estimation and up-scaling purposes. Finally, it was revealed that the plant diversity of the landscape depends, to a large extent, on the diversity contained in the most mature forest class, which is also the most diverse community in the studied area. High and moderate beta diversity values between mature forests and both the secondary associations and the first stages of succession, respectively, indicated that there is a significant contribution to the diversity of the landscape by those vegetation classes.     

Nutritional Requirements of <Emphasis Type="Italic">Lactobacillus delbrueckii</Emphasis> subsp. <Emphasis Type="Italic">lactis</Emphasis> in a Chemically Defined Medium

This study was undertaken to determine the nutritional requirements of Lactobacillus delbrueckii subsp. lactis and to develop a minimal chemically defined medium that supports sustained growth of these microorganisms. The single-omission technique was applied to each component of complete chemically defined medium in order to determine the nutritional requirements. L. delbrueckii subsp. lactis was prototrophic for alanine, glycine, aspartic acid, asparagine, glutamine, threonine, and proline. The lysine requirement was strain-dependent. Magnesium was the only essential oligoelement. These microorganisms also required uracil and guanine and adenine as pyrimidine and purine sources, respectively. In view of the nutritional requirements we designed a new minimal defined medium which supports sustained growth of L. delbrueckii subsp. lactis. This medium is simple and well defined, and should be preferable to complex media for conducting future biochemical, physiological, and genetic studies on L. delbrueckii subsp. lactis.