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Winking J 《Social biology》2006,53(1-2):100-115
Human pair-bonding and paternal involvement have long been attributed to the need for biparental rearing of altricial offspring with extended periods of dependency. More recently, researchers have focused on the fertility benefits that pair-bonding offers men and have re-conceptualized paternal care as a stratagem designed to curry favor with the recipient children's mother. These models, however, fail to explain a number of puzzling empirical findings, namely the lack of a significant and robust effect of father-presence cross-culturally, despite what appears to be true paternal involvement. I argue that the record is better explained by conceptualizing reproduction within unions as a joint venture, in which men's contributions are not simply lumped onto women's invariant levels of parental investment, but one in which men's involvement allows wives to reduce their own allocations to parental investment and increase those to fertility (fertility model), thereby maximizing the production of the union, not simply child survivorship. 相似文献
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Do people think that scientists are bad people? Although surveys find that science is a highly respected profession, a growing discourse has emerged regarding how science is often judged negatively. We report ten studies (N = 2328) that investigated morality judgments of scientists and compared those with judgments of various control groups, including atheists. A persistent intuitive association between scientists and disturbing immoral conduct emerged for violations of the binding moral foundations, particularly when this pertained to violations of purity. However, there was no association in the context of the individualizing moral foundations related to fairness and care. Other evidence found that scientists were perceived as similar to others in their concerns with the individualizing moral foundations of fairness and care, yet as departing for all of the binding foundations of loyalty, authority, and purity. Furthermore, participants stereotyped scientists particularly as robot-like and lacking emotions, as well as valuing knowledge over morality and being potentially dangerous. The observed intuitive immorality associations are partially due to these explicit stereotypes but do not correlate with any perceived atheism. We conclude that scientists are perceived not as inherently immoral, but as capable of immoral conduct. 相似文献
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The relationship between inflammation and insulin resistance is complex and not fully understood. Patients with rheumatoid arthritis are at increased risk of mortality from cardiovascular disease, which is known to be associated with insulin resistance. In the previous issue of Arthritis Research & Therapy, Ormseth and colleagues report the results of an 8-week trial of pioglitazone, an agent commonly used to treat type 2 diabetes mellitus, upon the DAS-28 (disease activity score using 28 joint counts). Modest improvements in the DAS-28 CRP (DAS-28 C-reactive protein) were shown, with no effect on DAS-28 ESR (DAS-28 erythrocyte sedimentation rate). Other variables that improved with pioglitazone were the CRP, IL-6, and patient-reported assessment of global health. The authors discuss the contribution of insulin resistance to the inflammation noted in rheumatoid arthritis. 相似文献
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Saman Rasoul Jan Paul Ottervanger Jan-Henk E Dambrink Menko-Jan de Boer Jan CA Hoorntje AT Marcel Gosselink Felix Zijlstra Harry Suryapranata Arnoud WJ van't Hof 《BMC cardiovascular disorders》2007,7(1):1-7
Background
We have previously documented significant differences in orthogonal P wave morphology between patients with and without paroxysmal atrial fibrillation (PAF). However, there exists little data concerning normal P wave morphology. This study was aimed at exploring orthogonal P wave morphology and its variations in healthy subjects.Methods
120 healthy volunteers were included, evenly distributed in decades from 20–80 years of age; 60 men (age 50+/-17) and 60 women (50+/-16). Six-minute long 12-lead ECG registrations were acquired and transformed into orthogonal leads. Using a previously described P wave triggered P wave signal averaging method we were able to compare similarities and differences in P wave morphologies.Results
Orthogonal P wave morphology in healthy individuals was predominately positive in Leads X and Y. In Lead Z, one third had negative morphology and two-thirds a biphasic one with a transition from negative to positive. The latter P wave morphology type was significantly more common after the age of 50 (P < 0.01). P wave duration (PWD) increased with age being slightly longer in subjects older than 50 (121+/-13 ms vs. 128+/-12 ms, P < 0.005). Minimal intraindividual variation of P wave morphology was observed.Conclusion
Changes of signal averaged orthogonal P wave morphology (biphasic signal in Lead Z), earlier reported in PAF patients, are common in healthy subjects and appear predominantly after the age of 50. Subtle age-related prolongation of PWD is unlikely to be sufficient as a sole explanation of this finding that is thought to represent interatrial conduction disturbances. To serve as future reference, P wave morphology parameters of the healthy subjects are provided. 相似文献7.
Estimates of molecular genetic variation are often used as a cheap and simple surrogate for a population's adaptive potential, yet empirical evidence suggests they are unlikely to be a valid proxy. However, this evidence is based on molecular genetic variation poorly predicting estimates of adaptive potential rather than how well it predicts true values. As a consequence, the relationship has been systematically underestimated and the precision with which it could be measured severely overstated. By collating a large database, and using suitable statistical methods, we obtain a 95% upper bound of 0.26 for the proportion of variance in quantitative genetic variation explained by molecular diversity. The relationship is probably too weak to be useful, but this conclusion must be taken as provisional: less noisy estimates of quantitative genetic variation are required. In contrast, and perhaps surprisingly, current sampling strategies appear sufficient for characterising a population's molecular genetic variation at comparable markers. 相似文献
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Bräuer J Call J Tomasello M 《Proceedings. Biological sciences / The Royal Society》2006,273(1605):3123-3128
Brosnan et al. (Brosnan, S. F. Schiff, H. C. & de Waal, F. B. M. 2005 Tolerance for inequity may increase with social closeness in chimpanzees. Proc. R. Soc. B272, 253-258) found that chimpanzees showed increased levels of rejection for less-preferred food when competitors received better food than themselves and postulated as an explanation inequity aversion. In the present study, we extended these findings by adding important control conditions, and we investigated whether inequity aversion could also be found in the other great ape species and whether it would be influenced by subjects' relationship with the competitor. In the present study, subjects showed a pattern of food rejection opposite to the subjects of the above study by Brosnan et al. (2005). Our apes ignored fewer food pieces and stayed longer in front of the experimenter when a conspecific received better food than themselves. Moreover, chimpanzees begged more vigorously when the conspecific got favoured food. The most plausible explanation for these results is the food expectation hypothesis - seeing another individual receive high-quality food creates the expectation of receiving the same food oneself - and not inequity aversion. 相似文献
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《Studies in History and Philosophy of Science Part C: Studies in History and Philosophy of Biological and Biomedical Sciences》2013,44(3):309-311
It is commonly thought that natural selection explains the rise of adaptive complexity. Razeto-Barry and Frick (2011) have recently argued in favour of this view, dubbing it the Creative View. I argue that the Creative View is mistaken if it claims that natural selection serves to answer Paley’s question. This is shown by a case that brings out the contrastive structure inherent in this demand for explanation. There is, however, a rather trivial sense in which specific environmental conditions are crucial for the rise of specific adaptations, but this is hardly what opponents of the Creative View are denying. 相似文献
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M H Ornstein E R Littlewood I M Baird J Fowler W R North A G Cox 《BMJ (Clinical research ed.)》1981,282(6273):1353
Fifty-eight patients with uncomplicated diverticular disease of the colon took bran crispbread, ispaghula drink, and placebo for four months each in a randomised, cross-over, double-blind controlled trial. Assessments were made subjectively, using a monthly self-administered questionnaire, and objectively, by examining a seven-day stool collection at the end of each treatment period. In terms of a pain score, lower bowel symptom score (the pain score and sensation of incomplete emptying, straining, stool consistency, flatus, and aperients taken), and total symptom score (belching, nausea, vomiting, dyspepsia, and abdominal distension) fibre supplementation conferred no benefit. Symptoms of constipation, however, when assessed alone, were significantly relieved. Both fibre regimens produced the expected changes in stool weight, consistency, and frequency. It is concluded that dietary fibre supplements in the commonly used doses do no more than relieve constipation. Perhaps the impression that fibre helps diverticular disease is simply a manifestation of Western civilisation''s obsession with the need for regular frequent defecation. 相似文献
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During natural human locomotion, neural connections are activated that are typical of regulation of the quadrupedal walking. The interaction between the neural networks generating rhythmic movements of the upper and lower limbs depends on tonic state of each of these networks regulated by motor signals from the brain. Distortion of these signals in patients with Parkinson’s disease (PD) may lead to disruption of the interlimb interactions. We examined the effect of movements of the limbs of one girdle on the parameters of the motor activity of another limb girdle at their joint cyclic movements under the conditions of arm and leg unloading in 17 patients with PD and 16 healthy subjects. We have shown that, in patients, the effect of voluntary and passive movements of arms, as well as the active movement of the distal parts of arms, on the voluntary movement of legs is weak, while in healthy subjects, the effect of arm movements on the parameters of voluntary stepping is significant. The effect of arm movements on the activation of the involuntary stepping by vibrational stimulation of-legs in patients was absent, while in healthy subjects, the motor activity of arms increased the possibility of involuntary rhythmic movements activation. Differences in the effect of leg movements on the rhythmic movements of arms were found in both patients and healthy subjects. The interlimb interaction appeared after drug administration. However, the effect of the drug was not sufficient for the recovery of normal state of the neural networks in patients. In PD patients, neural networks generating stepping rhythm have an increased tonic activity, which prevents the activation and appearance of involuntary rhythmic movements facilitating the effects of arms on legs. 相似文献
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Celiac disease (gluten sensitive enteropathy) is a condition affecting the small bowel, characterized by permanent intolerance to dietary gluten, and giving rise to varying degrees of malabsorption and diarrhea. With the advent of sensitive screening tests, the condition is being increasingly diagnosed. Celiac disease is more common in the Irish and in those of Irish descent. Simoons (1978, 1981) hypothesized that the present-day prevalence of celiac disease across Europe is related to the interaction between genetic gradients, largely determined by the advance of agriculture, and historical patterns of cereal ingestion. This essay examines Simoons' hypothesis as it relates to Ireland, reviews the ethnic and genetic mix of those living on the island of Ireland and aspects of Irish dietary history, and considers how these factors may have combined to result in a high frequency of celiac disease. 相似文献
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Ferdane Kutlar Jose M. Gonzalez-Redondo Abdullah Kutlar Aytemiz Gurgey Çigdem Altay Georgi D. Efremov Klara Kleman Titus H. J. Huisman 《Human genetics》1989,82(2):179-186
Summary Details are given of a study of blood samples from 24 patients with Hb H disease from different Mediterranean countries and from the Far East. Four different types of -thal-1 (--) were observed, namely-() ( 20.5-kb deletion);--MED-I ( 17.5-kb deletion);--MED-II (>26.5-kb deletion); and--SEA ( 18-kb deletion, in Orientals only). The -thal-2 was mainly of the deletion type (16 with the 3.7-kb deletion; 1 with the 4.2-kb deletion), while 4 of the 7 patients with a nondeletional type had the five-nucleotide deletion at the donor splice site of the first intron of the 2 gene. All patients had a mild-to-moderate hemolytic anemia; no significant differences in hematology were observed between the groups. Hb A2 was decreased to about one-third of the normal level. The Hb H formation varied considerably and its quantitation was not always satisfactory. Patients with Hb H disease due to any -thal-1 combined with a nondeletional -thal-2 had the highest Hb H levels and a more marked anemia. The chain production was small and absent in patients with the MED-II type of -thal-1 because this deletion included the and genes. The highest chain levels were present in the four patients with the SEA type of -thal-1. The chain production was increased, particularly in patients with a mutation of C T at position-158 to the G globin gene. This chain was primarily present as Hb Bart's (or 4) and only about 15% was recovered as Hb F or 22. The evaluation of the rate of chains produced in these patients was greatly facilitated by data from one patient who had Hb H disease and a heterozygosity for the A-+. The low levels of Hb A2 and of Hb F (relative to Hb Bart's) can be explained by a decreased affinity of chains for and chains as compared with chains in conditions of severe chain deficiency. 相似文献
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Objective: The objective of this study is to explore the cytokines in serum, synovial fluid as potential biomarkers of Kashin–Beck disease (KBD) and to further understand the role of these cytokines in the pathogenesis of KBD.Methods: A systematic electronic database search was performed from inception up to 15 March 2015. Meta-analysis was performed for cytokines more than one repetition in studies with available data. The effect size was summarized as standardized mean difference (SMD) with 95% confidence intervals (CIs) by a random effect model.Results: A total of 18 articles were included. The pooled standardized mean differences showed the serum levels of tumor necrosis factor alpha (2.72, 95% CI: 1.8 5–3.59), interleukin-1 beta (1.21, 95% CI: 0.6 1–1.80), and nitric oxide (2.60, 95% CI: 1.5 2–3.68) were significantly higher in adult KBD patients compared with that in healthy controls.Conclusions: There was explicit evidence showing that the tumor necrosis factor alpha, interleukin-1 beta and nitric oxide were closely related to the presence of KBD, and these cytokines played a vital role in the pathogenesis of KBD. 相似文献
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A. V. Alessenko 《Biochemistry (Moscow) Supplemental Series B: Biomedical Chemistry》2013,7(2):108-123
The review discusses the functional role of sphingolipids in the pathogenesis of Alzheimer’s disease (AD). Certain evidence exists that the imbalance of sphingolipids such as sphingomyelin, ceramide, sphingosine, sphingosine-1-phosphate and galactosylceramide in the brain of animals and humans, in the cerebrospinal fluid and blood plasma of AD patients plays a crucial role in neuronal function by regulating growth, differentiation and cell death in CNS. Activation of sphingomyelinase (Smase), which leads to the accumulation of the proapoptotic agent, ceramide, can be considered as a new mechanism for AD and may be a prerequisite for the treatment of this disease by using drugs that inhibit SMase activity. The role of sphingolipids as biomarkers for the diagnosis of the early stage of Alzheimer’s disease and monitoring the effectiveness of treatment with new drugs is discussed. 相似文献
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