Qualitative Insights and Methodological Challenges: Next Steps in Research on Low-Income Fathering

For decades, researchers have struggled to assess the characteristics and lived experiences of low-income men on the margins of their families. Recent initiatives, such as the Fatherhood Research Initiative, the DADS project, and related multi-site evaluations, have resulted in promising longitudinal data on low-income men's parenting behavior and subsequent effects on their children's development and well-being. However, limitations that linger in this research urge consideration of new approaches to the study of low-income fatherhood. In this chapter we identify four areas for critical consideration in research on low-income fathers and their children. We explore the range of qualitative tools that are available to address these challenges and discuss potential methodological innovations, including mixed methodological and multidisciplinary approaches in the study of low-income fathering.     

The Study of Territoriality: Complexities and Future Directions

Each paper in an American Society of Zoologists' symposium onterritoriality generated new ideas for future research. However,since similar themes repeatedly arose, an overview of the symposiumrevealed the areas in which future research is most needed.Theory far outstrips data on territoriality at this point, andefforts should concentrate on field tests of ideas. Some ofthe general areas that need study are: the effect of foraginggoals and constraints on territorial decisions, the effect ofthe internal energy or breeding state of the animal in makingterritorial decisions, the effects of subtle factors such ashabitat geometry and the role of neighbors on the cost of defense,the effect of various forms of environmental variability onterritorial decisions, the active or passive influence of plantson territoriality, and the effect of scale and mobility in theexpression and evolution of territoriality. The study of territorialityis entering a particularly challenging stage of development,because study systems must be carefully chosen and model assumptionsthoroughly examined before rigorous experimental tests of hypothesescan be performed. Yet the state of the art is such now thatonly rigorous tests will advance our knowledge further.     

《本草图经》建州产植物药图考证

《本草图经》所附药图中标明为福建产的药物有22种,其中建州(今属福建南平地区)产有3种,分别为建州天门冬、建州前胡、建州栀子。对其药图及文字记载进行考证,认为建州天门冬应为今之百合科植物天门冬[Asparagus cochinchinensis (Lour.) Merr.],建州前胡应为今之伞形科植物隔山香[Ostericum citriodorum (Hance) Yuan et Shan],建州栀子应为今之茜草科植物栀子(Gardenia jasminoides Ellis)。     

The Methodology of Studying Fathers in Child Development Research

Father studies, in general, are classified into two broad groups, depending on whether the focus is primarily on (1) becoming a father or (2) being a father. This article discusses the challenges researchers face when designing studies to examine the process of being a father and the approaches that are used to meet these challenges. Studies of men's involvement with their children must decide on which men to include and not to include as fathers, the steps that must be taken to identify fathers, how to obtain fathers' cooperation, and how to measure father involvement. This article discusses each of these and how decisions are influenced why whether or not fathers who do not live with their children are included in the study. The father component of the Early Childhood Longitudinal Study, Birth Cohort is used to illustrate how one being a father study approached these challenges.     

Fathering of Dizygotic Twins and Risk of Prostate Cancer: Nationwide,Population-Based Case-Control Study

Background

An association between male fertility and risk of prostate cancer has been suggested, possibly through lower androgen levels in subfertile men. We evaluated male fertility in relation to risk of prostate cancer by assessing the frequency of fathering of dizygotic twins, a marker of high fertility, among cases of prostate cancer and controls.

Methods

We performed a case-control study in Prostate Cancer data Base Sweden (PCBaSe), a nationwide, population-based cohort. PCBaSe was linked to the Swedish twin register for information on zygosity for same-sex twins and to other nationwide health care registers and demographic databases for information on socioeconomic factors, comorbidity, and tumor characteristics for 96 301 prostate cancer cases and 378 583 matched controls. To account for the influence of in vitro fertilization on dizygotic twinning, analyses were restricted to men who had fathered children before 1991, when in vitro fertilization was still uncommon in Sweden.

Results

1 112 cases and 4 538 controls had fathered dizygotic twins. Men with dizygotic twins had no increased risk of prostate cancer compared to fathers of singletons; neither for total prostate cancer odds ratio (OR) 0.95(95% CI 0.89–1.02), nor for any risk category, OR 0.97 (95% CI 0.84–1.12) for low-risk disease, and OR 1.04 (95% CI 0.90–1.22) for metastatic disease.

Conclusion

The lack of association between fathering of dizygotic twins and prostate cancer risk give no support for an association between male fertility and prostate cancer risk.     

Infrared imaging microscopy of bone: Illustrations from a mouse model of Fabry disease

Bone is a complex tissue whose composition and properties vary with age, sex, diet, tissue type, health and disease. In this review, we demonstrate how infrared spectroscopy and infrared spectroscopic imaging can be applied to the study of these variations. A specific example of mice with Fabry disease (a lipid storage disease) is presented in which it is demonstrated that the bones of these young animals, while showing typical spatial variation in mineral content, mineral crystal size, and collagen maturity, do not differ from the bones of age- and sex-matched wild type animals.     

Early Vascular Aging in Young and Middle-Aged Ischemic Stroke Patients: The Norwegian Stroke in the Young Study

Background

Ischemic stroke survivors have high risk of cardiovascular morbidity and mortality even at young age, suggesting that early arterial aging is common among such patients.

Methods

We measured aortic stiffness by carotid-femoral pulse wave velocity (PWV) in 205 patients (69% men) aged 15–60 years with acute ischemic stroke in the prospective Norwegian Stroke in the Young Study. High for age carotid-femoral PWV was identified in the reference normogram.

Results

Patients were on average 49±10 years old, 34% had a history of hypertension and 37% had metabolic syndrome (MetS). In the total study population, higher PWV was associated with history of hypertension (β = 0.18), higher age (β = 0.34), systolic blood pressure (BP) (β = 0.28) and serum creatinine (β = 0.18) and lower high-density lipoprotein (HDL) cholesterol (β = –0.10, all p<0.01) in multivariate linear regression analysis (multiple R² = 0.42, p<0.001). High for age PWV was found in 18% of patients. In univariate analyses, known hypertension was associated with a 6-fold, MetS with a 4-fold and presence of carotid plaque with a 3.7-fold higher risk for high for age PWV (all p<0.01). In multiple logistic regression analysis higher systolic BP (odds ratio [OR] 1.04; 95% confidence interval [CI] 1.02–1.06; p<0.01), history of hypertension (OR 3.59; 95% CI 1.52–8.51; p<0.01), low HDL cholesterol (OR 3.03; 95% CI 1.00–9.09; p = 0.05) and higher serum creatinine (OR 1.04; 95% CI 1.01–1.06; p<0.01) were associated with high for age PWV.

Conclusions

Higher PWV is common in younger and middle-aged ischemic stroke patients and associated with a clustering of classical cardiovascular risk factors.ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT01597453","term_id":"NCT01597453"}}NCT01597453     

自然哺乳长颈鹿的幼仔行为研究

对成都动物园2005年和2008年出生长颈鹿幼仔在母兽哺乳情况下的1月龄内幼仔行为进行了观察和分析.发现幼长颈鹿的主要行为有卧、走、站、吃奶、跑等,其中卧和站的行为分别占全天时间的61.7%和32.3%;幼长颈鹿在10 d左右开始学习采食青草,4周龄时明显能吃到一些青草.     

Complexities in the genetic dissection of quantitative trait loci

The analysis of complex traits, including those involved in many common diseases, has encountered significant difficulties, and, despite major efforts during the past decade, has had little success. Current advances in genomics, however, promise to change this. Recently, Steinmetz et al. used a new technique to produce the first complete quantitative trait locus (QTL) analysis of a complex trait from phenotype to gene to be published entirely in a single report. This marks a significant advance over previous QTL analyses, which took several years. The work exemplifies some of the complexities of QTL mapping and demonstrates a novel method to resolve the underlying genetic architecture of QTLs in yeast. Here we discuss this work in the general context of genetic dissection of complex traits and QTLs.     

Empirical Complexities in the Genetic Foundations of Lethal Mutagenesis

From population genetics theory, elevating the mutation rate of a large population should progressively reduce average fitness. If the fitness decline is large enough, the population will go extinct in a process known as lethal mutagenesis. Lethal mutagenesis has been endorsed in the virology literature as a promising approach to viral treatment, and several in vitro studies have forced viral extinction with high doses of mutagenic drugs. Yet only one empirical study has tested the genetic models underlying lethal mutagenesis, and the theory failed on even a qualitative level. Here we provide a new level of analysis of lethal mutagenesis by developing and evaluating models specifically tailored to empirical systems that may be used to test the theory. We first quantify a bias in the estimation of a critical parameter and consider whether that bias underlies the previously observed lack of concordance between theory and experiment. We then consider a seemingly ideal protocol that avoids this bias—mutagenesis of virions—but find that it is hampered by other problems. Finally, results that reveal difficulties in the mere interpretation of mutations assayed from double-strand genomes are derived. Our analyses expose unanticipated complexities in testing the theory. Nevertheless, the previous failure of the theory to predict experimental outcomes appears to reside in evolutionary mechanisms neglected by the theory (e.g., beneficial mutations) rather than from a mismatch between the empirical setup and model assumptions. This interpretation raises the specter that naive attempts at lethal mutagenesis may augment adaptation rather than retard it.     

Complexities in the denaturation of horse metmyoglobin by guanidine hydrochloride

The denaturation of horse metmyoglobin by guanidine hydrochloride was studied at pH 6.4 and 25 degrees C. Measurements of both the peptide circular dichroism and the absorbance in the Soret region suggest that the extent of renaturation strongly depends on the time interval during which the protein is exposed to concentrated solutions of the denaturant. From the equilibrium measurements of the absorption in the Soret region, it is concluded that the unfolding of metmyoglobin is complex. This is further supported by kinetic studies of denaturation which suggest the occurrence of the least four species in the reaction.     

Complexities of limb anomalies: the lower extremity in the "prune belly" phenotype

The so-called "prune belly" syndrome (PBS) consists of megalocystis, cryptorchidism, and marked abdominal distension; in addition to these findings, many other abnormalities are commonly present, rarely including severe anomalies of the leg. We report two such individuals, in whom PBS coexisted with abnormal development of the lower extremity. The first, a still-born male fetus, was delivered at 21 weeks gestation; generalized hypoplasia of both legs was present, more marked distally than proximally, and more severe on the left. The second case, a liveborn male infant, was the second of dichorionic twins, delivered at 33 weeks gestation; this infant died at two hours from respiratory insufficiency due to pulmonary hypoplasia. There was severe hypoplasia of the right leg, with gangrenous necrosis of all tissues distal to the knee. Additional findings included a single right umbilical artery, and a small congenital cystic adenomatoid malformation of the right lung. The findings in these cases are compared to other similar cases in the literature, and possible mechanisms for the etiology and pathogenesis of maldevelopment of the leg in PBS are discussed.     

Complexities in the analysis of cryptic taxa within the genus Anopheles

Grassi's discovery one hundred years ago brought to light the puzzle of anophelism without malaria in Europe. With the discovery of the European Anopheles maculipennis complex the puzzle was solved but the 'species problem' has not gone away. Meaningful epidemiologic studies and effective vector control programs depend upon efficient methods for discriminating among the major vectors, lesser vectors and non-vectors of ubiquitous anopheline sibling species complexes. We now have a variety of techniques for identifying cryptic species, ranging from crossing studies through morphological, cytogenetic, allozyme and repetitive DNA-based strategies. However, cytogenetic and molecular data can also be used to infer evolutionary relationships among cryptic taxa. This approach has been crucial to understanding the biology of the vector, and may illuminate the speciation process and the human impact upon this process. Nevertheless, the analysis of cryptic taxa has proven unexpectedly complex. Studies of An. funestus and An. gambiae reveal conflicts among classes of markers and between different genomic locations. The data are consistent with a model of speciation in which gene flow may still occur in parts of the genome, and they suggest that caution should be exercised in the interpretation of results from small numbers of loci, only one type of marker, and markers located in specific genomic regions such as chromosomal inversions.