共查询到20条相似文献,搜索用时 31 毫秒
1.
Jacob M. Vigil 《Human nature (Hawthorne, N.Y.)》2007,18(2):143-161
Several hypotheses on the form and function of sex differences in social behaviors were tested. The results suggest that friendship
preferences in both sexes can be understood in terms of perceived reciprocity potential—capacity and willingness to engage in a mutually beneficial relationship. Divergent social styles may in turn reflect trade-offs
between behaviors selected to maintain large, functional coalitions in men and intimate, secure relationships in women. The
findings are interpreted from a broad socio-relational framework of the types of behaviors that facilitate selective advertisement
and investment of reciprocity potential across individuals and within groups of men and women.
相似文献
Jacob M. VigilEmail: |
2.
Sub-Antarctic Marion Island has had a permanent research station for 50 years and the islands Wandering Albatrosses have been intensively studied for 20 years. The reactions of breeding birds to approaches by a human on foot were recorded. Three response variables were calculated: intensity of vocal reaction (IVR), intensity of non-vocal reaction (INR) and overall response index (ORI). At 5 m from the nest, twice as many birds stood and/or vocalised as at 15 m. Nearest neighbour distance, age and gender did not explain individual variability of responses. Study colony birds had higher IVR scores than non-study colony birds; birds at colonies closest to the station had the highest ORI scores. A better breeding record was associated with lower IVR and ORI scores, but a causative relationship remains to be demonstrated. A minimum viewing distance of 25 m is recommended for breeding Wandering Albatrosses.
相似文献
Marienne S. de VilliersEmail: Fax: +27-21-6503434 |
John CooperEmail: |
Peter G. RyanEmail: |
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Alejandro Rosas 《Biology & philosophy》2008,23(4):555-566
Recent developments in evolutionary game theory argue the superiority of punishment over reciprocity as accounts of large-scale
human cooperation. I introduce a distinction between a behavioral and a psychological perspective on reciprocity and punishment
to question this view. I examine a narrow and a wide version of a psychological mechanism for reciprocity and conclude that a narrow version is clearly distinguishable from punishment, but inadequate for
humans; whereas a wide version is applicable to humans but indistinguishable from punishment. The mechanism for reciprocity
in humans emerges as a meta-norm that governs both retaliation and punishment. I make predictions open to empirical investigation
to confirm or disconfirm this view.
相似文献
Alejandro RosasEmail: |
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The recent contribution by Jarmila Kukalová-Peck on Hennigian phylogenetics and hexapod limb evolution is critically evaluated.
相似文献
Michael S. Engel (Corresponding author)Email: |
8.
Cooperative child care among humans, where individuals other than the biological mother (allomothers) provide care, may increase
a mother’s fertility and the survivorship of her children. Although the potential benefits to the mother are clear, the motivations
for allomothers to provide care are less clear. Here, we evaluate the kin selection allomothering hypothesis using observations
on Hadza hunter-gatherers collected in ten camps over 17 months. Our results indicate that related allomothers spend the largest
percentage of time holding children. The higher the degree of relatedness among kin, the more time they spend holding, supporting
the hypothesis of nepotism as the strongest motivation for providing allomaternal care. Unrelated helpers of all ages also
provide a substantial amount of investment, which may be motivated by learning to mother, reciprocity, or coercion.
相似文献
Frank W. MarloweEmail: |
9.
Peter Godfrey-Smith 《Biology & philosophy》2007,22(3):429-437
Jablonka and Lamb's claim that evolutionary biology is undergoing a ‘revolution’ is queried. But the very concept of revolutionary
change has uncertain application to a field organized in the manner of contemporary biology. The explanatory primacy of sequence
properties is also discussed.
相似文献
Peter Godfrey-SmithEmail: |
10.
Does Investment in the Sexes Differ When Fathers Are Absent? 总被引:1,自引:1,他引:0
Mhairi A. Gibson 《Human nature (Hawthorne, N.Y.)》2008,19(3):263-276
This study examines child survival and growth in a patrilineal Ethiopian community as a function of father absence and sex.
In line with evolutionary predictions for sex-biased parental investment, the absence of a father and associated constraints
on household resources is more detrimental for sons’ than daughters’ survival in infancy. Father absence doubles a son’s risk
of dying in infancy but has a positive influence on the well-being of female members of the household, improving daughter
survival, growth, and maternal nutritional status. Lack of paternal investment may be compensated for by other matrilateral
kin through increased reciprocity between mother, daughter, and sister.
相似文献
Mhairi A. GibsonEmail: |
11.
Per-Ola Norrby Knud J. Jensen 《International journal of peptide research and therapeutics》2006,12(4):335-339
Acidolytic release of an amide from a solid support by C–N bond cleavage is an ubiquitous and crucial step in many solid-phase syntheses. We have used molecular modeling of a pseudo-equilibrium to explore substituent and steric effects in the release of peptides. The high acid-lability of the backbone amide linkage (BAL), which releases sec. amides, compared to C-terminal amide anchoring, which releases primary amides, was rationalized by steric relief upon cleavage. Thus, the relative stability of the carbenium ion formed from the linker in the acidolytic release is an insufficient measure of the lability of a linkage. In addition, predictions indicated that steric effects from the Cα-substituent in a BAL anchored amino acid residue should accelerate the acidolytic release. The finding that steric crowding leads to increased acid-lability will be important for further development and use of handles.
相似文献
Knud J. JensenEmail: |
12.
Methanogens growing on C-1 substrates synthesize 2-carbon acetyl groups in the form of acetyl-CoA for carbon assimilation
using the multienzyme complex acetyl-CoA decarbonylase/synthase (ACDS) which contains five different subunits encoded within
an operon. In species growing on acetate ACDS also functions to cleave the acetate C-C bond for energy production by methanogenesis.
A number of species of Methanosarcina that are capable of growth on either C-1 compounds or acetate contain two separate ACDS operons, and questions have been
raised about whether or not these operons play separate roles in acetate synthesis and cleavage. Methanosarcina thermophila genomic DNA was analyzed for the presence of two ACDS operons by PCR amplifications with different primer pairs, restriction
enzyme analyses, DNA sequencing and Southern blot analyses. A single ACDS operon was identified and characterized, with no
evidence for more than one. MALDI mass spectrometric analyses were carried out on ACDS preparations from methanol- and acetate-grown
cells. Peptide fragmentation patterns showed that the same ACDS subunits were present regardless of growth conditions. The
evidence indicates that a single form of ACDS is used both for acetate cleavage during growth on acetate and for acetate synthesis
during growth on C-1 substrates.
Electronic Supplementary Material Supplementary material is available for this article at
相似文献
David A. Grahame (Corresponding author)Email: |
Edward DeMoll (Corresponding author)Email: |
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Peter beim Graben Dimitris Pinotsis Douglas Saddy Roland Potthast 《Cognitive neurodynamics》2008,2(2):79-88
We construct a mapping from complex recursive linguistic data structures to spherical wave functions using Smolensky’s filler/role
bindings and tensor product representations. Syntactic language processing is then described by the transient evolution of
these spherical patterns whose amplitudes are governed by nonlinear order parameter equations. Implications of the model in
terms of brain wave dynamics are indicated.
Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.
相似文献
Peter beim GrabenEmail: |
16.
Machado RR Lima Filho ES Jardim DF Ferreira MA de Faria CG Duarte RS Lesche B 《European biophysics journal : EBJ》2008,38(1):111-119
An interferometer that measures the refractive index changes due to bacterial metabolism is described. The apparatus permits
simultaneous and real time measurement of bacterial growth in several samples of slowly growing mycobacteria. The error sources
are discussed and the sensitivity of the apparatus is tested. For the species Mycobacterium bovis BCG and M. smegmatis, a relation between refractive index change and bacterial concentration is determined experimentally and the time constant
of bacterial growth is measured.
相似文献
B. LescheEmail: |
17.
Joel D. Velasco 《Biology & philosophy》2009,24(4):473-486
A natural starting place for developing a phylogenetic species concept is to examine monophyletic groups of organisms. Proponents
of “the” Phylogenetic Species Concept fall into one of two camps. The first camp denies that species even could be monophyletic
and groups organisms using character traits. The second groups organisms using common ancestry and requires that species must
be monophyletic. I argue that neither view is entirely correct. While monophyletic groups of organisms exist, they should
not be equated with species. Instead, species must meet the more restrictive criterion of being genealogically exclusive groups
where the members are more closely related to each other than to anything outside the group. I carefully spell out different
versions of what this might mean and arrive at a working definition of exclusivity that forms groups that can function within
phylogenetic theory. I conclude by arguing that while a phylogenetic species concept must use exclusivity as a grouping criterion,
a variety of ranking criteria are consistent with the requirement that species can be placed on phylogenetic trees.
相似文献
Joel D. VelascoEmail: |
18.
A key point in the analysis of dynamical models of biological systems is to handle systems of relatively high dimensions.
In the present paper we propose a method to hierarchically organize a certain type of piecewise affine (PWA) differential
systems. This specific class of systems has been extensively studied for the past few years, as it provides a good framework
to model gene regulatory networks. The method, shown on several examples, allows a qualitative analysis of the asymptotic
behavior of a PWA system, decomposing it into several smaller subsystems. This technique, based on the well-known strongly
connected components decomposition, is not new. However, its adaptation to the non-smooth PWA differential equations turns
out to be quite relevant because of the strong discrete structure underlying these equations. Its biological relevance is
shown on a 7-dimensional PWA system modeling the gene network responsible for the carbon starvation response in Escherichia coli.
相似文献
Laurent Tournier (Corresponding author)Email: |
Jean-Luc GouzéEmail: |
19.
Paul F. Cannon Nigel L. Hywel-Jones Norbert Maczey Lungten Norbu Tshitila Tashi Samdup Phurba Lhendup 《Biodiversity and Conservation》2009,18(9):2263-2281
The insect-pathogenic fungus Ophiocordyceps sinensis (better known as Cordyceps sinensis) is harvested over much of the Himalayan plateau as a highly prized remedy in traditional Oriental medicine. Over the past
10 years its financial value has increased dramatically, with collectors paid as much as US $12,500 kg−1 for top-quality material. This is causing significant distortion to local economies, and there is widespread concern that
the current rate of collection is unsustainable. This paper introduces the fungus and its insect hosts, documents some of
the biological and social constraints to achieving sustainability, describes the socioeconomic climate within which harvest
and sale occurs in Bhutan, and details the measures put in place by the Royal Government of Bhutan to promote wise management
of this valuable natural resource.
相似文献
Paul F. CannonEmail: |
20.
Causal Explanation of Indonesian Forest Fires: Concepts, Applications, and Research Priorities 总被引:1,自引:0,他引:1
Andrew P. Vayda 《Human ecology: an interdisciplinary journal》2006,34(5):615-635
Problems with studies, claims, and assumptions that have been made about the causes of fires in Indonesia's tropical moist forests are identified, and the kinds of concepts, methods, prioritizing, and data needed to resolve the problems are discussed. Separate sections are devoted to studying ignitions, studying fire susceptibility and fire behavior, and using the goal of causal explanation to guide interdisciplinary research.
相似文献
Andrew P. VaydaEmail: |