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1.
Yossi Yovel Maya Geva-Sagiv Nachum Ulanovsky 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2011,197(5):515-530
Echolocating bats of the genus Rousettus produce click sonar signals, using their tongue (lingual echolocation). These signals are often considered rudimentary and
are believed to enable only crude performance. However, the main argument supporting this belief, namely the click’s reported
long duration, was recently shown to be an artifact. In fact, the sonar clicks of Rousettus bats are extremely short, ~50–100 μs, similar to dolphin vocalizations. Here, we present a comparison between the sonar systems
of the ‘model species’ of laryngeal echolocation, the big brown bat (Eptesicus fuscus), and that of lingual echolocation, the Egyptian fruit bat (Rousettus aegyptiacus). We show experimentally that in tasks, such as accurate landing or detection of medium-sized objects, click-based echolocation
enables performance similar to laryngeal echolocators. Further, we describe a sophisticated behavioral strategy for biosonar
beam steering in clicking bats. Finally, theoretical analyses of the signal design—focusing on their autocorrelations and
wideband ambiguity functions—predict that in some aspects, such as target ranging and Doppler-tolerance, click-based echolocation
might outperform laryngeal echolocation. Therefore, we suggest that click-based echolocation in bats should be regarded as
a viable echolocation strategy, which is in fact similar to the biosonar used by most echolocating animals, including whales
and dolphins. 相似文献
2.
Pasquale Stano 《Origins of life and evolution of the biosphere》2007,37(4-5):439-444
In this short article I discuss the relevance of two aspects of vesicle reactivity that are germane to understand the role
of compartments in the origin of early cells. Studies of vesicle self-reproduction indicate that simple vesicles can grow
and divide, maintaining inside most of their content and giving rise to a simple autopoietic system. New aspects of vesicle
reactivity are also introduced, such as selection and competition processes within vesicle populations, emphasizing the concepts
of vesicle diversity, inter-vesicles and vesicles–environment interactions, intended as synthetic analogs of primitive ‘ecological’
processes.
Presented at: International School of Complexity – 4th Course: Basic Questions on the Origins of Life; “Ettore Majorana” Foundation and Centre for Scientific Culture, Erice, Italy, 1–6 October 2006. 相似文献
3.
David Hunkeler 《The International Journal of Life Cycle Assessment》1999,4(5):291-298
Metrics are a prerequisite for the successful monitoring and management of progress toward goals. Within the context of sustainable
development these “values” are stakeholder dependent with the interests of the individual, society, the environmental infrastructure
and intergenerational liability differing significantly. These stakeholder priorities may also be mutually inconsistent or
simultaneously unattainable. Therefore, a set of scale- and value-specific indicators will he required to represent the priorities
of individuals, religious organizations, political and public interest groups, non-government organizations, firms and industry
associations, as well as national and international institutions. Restricting the number of ecometrics, or creating aggregated
sustainability indicators, risks disenfranchisement and ivalidation respectively.
Over the past three decades a series ofmicroecometrics have been developed to account for the impact of human activity, technology or products over regional, national, and sub-continental
scales. These include life cycle energy consumption, dematerialization, waste minimization, as well as design for environment
and eco-efficiency indicators, the latter two combining technological or economic aspects respectively with environmental
factors.Metrics which evaluate the impact of a service, or the utility provided by a product, are lacking. A series of global measures, or macroecometrics have also been defined and include the average annual temperature as well
as atmospheric compositions and concentrations, sea level, and earth based resources such as topsoil quantities. The validity
of microecometrics as measures of global phenomena can be established through life cycle impact assessments which evaluate
the “system’s” response to effects of products or services throughout their life cycle. However, the link between microecometrics
and macroecometrics, their validity as indicators of sustainability, the subjectivity of sustainable developmentper se as a value, and the relationship of metrics and sustainable development with family values has not extensively been addressed.
This paper summarizes recently proposed ecometrics, calls for the recognition of the subjectivity of indicators, the distinction
between ecometrics used for internal corporate reporting and external decision making, and the establishment of a representative
multistakeholder debate. 相似文献
4.
Kathelijne Koops William C. McGrew Tetsuro Matsuzawa 《Primates; journal of primatology》2010,51(2):175-178
Wild chimpanzees (Pan troglodytes) are renowned for their use of tools in activities ranging from foraging to social interactions. Different populations across
Africa vary in their tool use repertoires, giving rise to cultural variation. We report a new type of percussive technology
in food processing by chimpanzees in the Nimba Mountains, Guinea: Treculia fracturing. Chimpanzees appear to use stone and wooden “cleavers” as tools, as well as stone outcrop “anvils” as substrate
to fracture the large and fibrous fruits of Treculia africana, a rare but prized food source. This newly described form of percussive technology is distinctive, as the apparent aim is
not to extract an embedded food item, as is the case in nut cracking, baobab smashing, or pestle pounding, but rather to reduce
a large food item to manageably sized pieces. Furthermore, these preliminary data provide the first evidence of chimpanzees
using two types of percussive technology for the same purpose. 相似文献
5.
David G. Post 《International journal of primatology》1982,3(4):403-430
The results of an 11-month field study of the feeding behavior of adult yellow baboons (Papio cynocephalus)are presented. Although catholic feeders, the baboons are not unselective in their choice of foods, and a small number of
foods account for the bulk of their feeding time and are significant determinants of their home-range utilization patterns.
These preferred foods are consumed throughout the year, a response, perhaps, to relatively minor fluctuations in their availability.
Seasonal changes in food abundance are, however, reflected in other aspects of the baboons’ feeding behavior, including a
tendency to show greater day- to- day dietary variability during periods of higher rainfall and greater overall food availability.
It is suggested that this, and other, aspects of baboon feeding behavior can be understood only in the context of the extremely
“patchy” distribution of their food supplies. 相似文献
6.
7.
Athrycia cinerea Coq. is a univoltine parasitoid of the bertha armyworm,Mamestra configurata Walker (Lepidoptera: Noctuidae), in western Canada. This parasitoid overwinters as a pupa in the soil. These pupae are less sensitive than their host to
increased cold stress caused by lower temperatures or danger durations of exposure. Exposure to −7.5°C for 140 days did not
significantly reduce survival. Survival decreased with exposure to temperatures from −10 to −20°C, but survival was 48% even
after 40 days exposure to −20°C. The frequency distribution ofA. cinerea puparia per host is highly contagious. Other aspects of the life history are described.
Contribution No. 1403 Winnipeg Research Station. 相似文献
8.
Advances in genetic analysis and biotechnology of the cultivated button mushroom, Agaricus bisporus 总被引:1,自引:0,他引:1
During the last decade several major breakthroughs have been achieved in mushroom biotechnology, which greatly enhanced classical
mushroom breeding. DNA-based technologies such as restriction fragment length polymorphisms and randomly amplified polydisperse
DNA sequences have allowed for a measure of genetic diversity, for the isolation of homokaryons, for the determination of
inheritance of nuclear and mitochondrial markers, and for the production of a genetic linkage map. The recent availability
of ready-to-use and affordable DNA technologies has resulted in a substantial increase in the number of Agaricus bisporus genes that have been identified and characterized. A major breakthrough was achieved in 1996 when the first successful and
stable transformation system of A. bisporus was reported. Together, the availability of an increasing number of known genes and the possibility to produce transgenic
mushrooms will result in a better understanding of the molecular, physiological and biochemical processes that are essential
for mushroom production, shelf life and quality aspects such as flavor, texture and disease resistance. Some potential targets
for strain improvement are discussed, such as the genes involved in brown discoloration, substrate utilization, carbon and
nitrogen metabolism, and fruit body development.
Received: 19 January 1999 / Received revision: 27 May 1999 / Accepted: 4 June 1999 相似文献
9.
N. Rashevsky 《Bulletin of mathematical biology》1967,29(1):139-152
The discussion as to whether societies are organisms andvice versa has been going on for a long time. The question is meaningless unless a clear definition of the term “organism” is made.
Once such a definition is made, the question may be answered by studying whether there exists any relational isomorphism between
what the biologist calls an organism and what the sociologist calls society. Such a study should also include animal societies
studied by ecologists. Both human and animal societies are sets of individuals together with certain other objects which are
the products of their activities. A multicellular organism is a set of cells together with some products of their activities.
A cell itself may be regarded as a set of genes together with the products of their activities because every component of
the cell is either directly or indirectly the result of the activities of the genes. Thus it is natural to define both biological
and social organisms as special kinds of sets. A number of definitions are given in this paper which define what we call here
organismic sets. Postulates are introduced which characterize such sets, and a number of conclusions are drawn. It is shown
that an organismic set, as defined here, does represent some basic relational aspects of both biological organisms and societies.
In particular a clarification and a sharpening of the Postulate of Relational Forces given previously (Bull. Math. Biophysics,28, 283–308, 1966) is presented. It is shown that from the basic definitions and postulates of the theory of organismic sets,
it folows that only such elements of those sets will aggregate spontaneously, which are not completely “specialized” in the
performance of only one activity. It is further shown that such “non-specialized” elements undergo a process of specialization,
and as a result of it their spontaneous aggregation into organismic sets becomes impossible. This throws light on the problem
of the origin of life on Earth and the present absence of the appearance of life by spontaneous generation. Some applications
to problems of ontogenesis and philogenesis are made. Finally the relation between physics, biology, and sociology is discussed
in the light of the theory of organismic sets. 相似文献
10.
Exploration and play were observed in eight troops of howler monkeys (Alouatta palliata) containing 56 young and 95 adults. The behavior patterns of seven age classes are described. There was a clear trend for
animals to spend less time in nonsocial exploration with increasing age, and for the frequency of social play to follow an
inverted “U” pattern, peaking in the early juvenile stage at 15–30 min per day. The howlers' specialization for eating large
quantities of difficult to digest plant matter affected their play: as the young became increasingly dependent on plant food
around the infants stage, there was a shift in their playtimes to allow for the energy demanding activity of digestion. This
and other aspects of howler behavior are related to a reinforcement theory of exploration and play. 相似文献
11.
Chronic abuse of amphetamines, such as d-amphetamine (AMPH) and d-methamphetamine, results in psychological dependence, a condition in which the drug produces a feeling of satisfaction and
a drive that requires periodic or continuous administration of the drug to produce overwhelming pleasure or to avoid discomfort
such as dysphoria. The dysphoric state of AMPH withdrawal has been recognized as depressive syndromes, such as anhedonia,
depression, anxiety, and social inhibition, in early drug abstinence. Medication for treatment of the dysphoric state is important
for AMPH abusers to avoid impulsive self-injurious behavior or acts that are committed with unconscious or uncontrolled suicidal
ideation. However, successful treatments for AMPH withdrawal remain elusive, since the exact molecular basis of the expression
of dysphoria has not been fully elucidated. This review focuses on the molecular aspects of AMPH withdrawal as indexed by
neurochemical parameters under a variety of injection regimens (for example, levels of brain monoamines and their metabolites,
and γ-aminobutyric acid, expression of genes and proteins involved in neuronal activity, and monoamine metabolism and availability)
in rodent models which exhibit significant phenotypic features relevant to the syndromes of AMPH withdrawal in humans. 相似文献
12.
Duong Tan Nhut Jaime A. Teixeira Da Silva C. R. Aswath 《In vitro cellular & developmental biology. Plant》2003,39(3):266-276
Summary The basic factor underlying the success of the tissue culture, large-scale micropropagation and genetic transformation of
any plant species is regeneration. This has been achieved over the years through the use of various-sized explants ranging
from protoplasts (small scale) to entire organs (large scale). Inherent problems underlie the use of either extreme, leading
to both nonspecific morphogenic reactions in the latter, or to undesired necrosis in the former. This review investigates
the importance of different aspects of a thin cell layer (TCL) explant, from its source to its size. TCLs, as a results of
their size and origin, in combination with other controllable factors such as media and environmental conditions, have shown
this system to be superior to the use of conventional explants. Numerous species that were previously unsuccessfully tissue-cultured
have, with the use of TCL technology, resulted in their successful micropropagation and regeneration. These successes, based
on the inherent qualities of the TCL explant—specific for a given species—are also examined. 相似文献
13.
Best practices in heterotrophic high-cell-density microalgal processes: achievements,potential and possible limitations 总被引:1,自引:0,他引:1
Bumbak F Cook S Zachleder V Hauser S Kovar K 《Applied microbiology and biotechnology》2011,91(1):31-46
Microalgae of numerous heterotrophic genera (obligate or facultative) exhibit considerable metabolic versatility and flexibility
but are currently underexploited in the biotechnological manufacturing of known plant-derived compounds, novel high-value
biomolecules or enriched biomass. Highly efficient production of microalgal biomass without the need for light is now feasible
in inexpensive, well-defined mineral medium, typically supplemented with glucose. Cell densities of more than 100 g l−1 cell dry weight have been achieved with Chlorella, Crypthecodinium and Galdieria species while controlling the addition of organic sources of carbon and energy in fedbatch mode. The ability of microalgae
to adapt their metabolism to varying culture conditions provides opportunities to modify, control and thereby maximise the
formation of targeted compounds with non-recombinant microalgae. This review outlines the critical aspects of cultivation
technology and current best practices in the heterotrophic high-cell-density cultivation of microalgae. The primary topics
include (1) the characteristics of microalgae that make them suitable for heterotrophic cultivation, (2) the appropriate chemical
composition of mineral growth media, (3) the different strategies for fedbatch cultivations and (4) the principles behind
the customisation of biomass composition. The review confirms that, although fundamental knowledge is now available, the development
of efficient, economically feasible large-scale bioprocesses remains an obstacle to the commercialisation of this promising
technology. 相似文献
14.
Lucília Domingues António A. Vicente Nelson Lima José A. Teixeira 《Biotechnology and Bioprocess Engineering》2000,5(4):288-305
A review on the main aspects associated with yeast flocculation and its application in biotechnological processes is presented.
This subject is addressed following three main aspects—the basics of yeast flocculation, the development of “new” flocculating
yeast strains and bioreactor development. In what concerns the basics of yeast flocculation, the state of the art on the most
relevant aspects of mechanism, physiology and genetics of yeast flocculation is reported. The construction of flocculating
yeast strains includes not only the recombinant constitutive flocculent brewer's yeast, but also recombinant flocculent yeast
for lactose metabolisation and ethanol production. Furthermore, recent work on the heterologous β-galactosidase production
using a recombinant flocculentSaccharomyces cerevisiae is considered. As bioreactors using flocculating yeast cells have particular properties, mainly associated with a high solid
phase hold-up, a section dedicated to its operation is presented. Aspects such as bioreactor productivity and culture stability
as well as bioreactor hydrodynamics and mass transfer properties of flocculating cell cultures are considered. Finally, the
paper concludes describing some of the applications of high cell density flocculation bioreactors and discussing potential
new uses of these systems. 相似文献
15.
Developments in destructive and non-destructive pathways for selective desulfurizations in oil-biorefining processes 总被引:8,自引:0,他引:8
L. Setti P. Farinelli S. Di Martino S. Frassinetti G. Lanzarini P. G. Pifferi 《Applied microbiology and biotechnology》1999,52(1):111-117
Biocatalytic desulfurization is still not a commercial technology, but conceptual engineering and sensitivity analyses have
shown that the approach is very promising. The purpose of this paper is to investigate further some aspects of the biodesulphurization
pathways, discussing the non-destructive pathway with the well-known Rhodococcus rhodochrous IGTS8. Findings revealed byproducts, such as 2′-hydroxybiphenyl (HBP), sulfite and sulfate, obtained by the desulfurization
of dibenzothiophene (DBT), to exert an inhibiting effect. The results suggest that IGTS8 may follow two different metabolic
pathways in stationary-growth-phase cells or under growing conditions. The first pathway is characterized by oxidative steps,
which convert DBT to DBT sulfoxide and to DBT sulfone. The sulfone is transformed to 2-(2′-hydroxyphenyl)benzene sulfinate
and then to HBP and sulfite by a sulfinic acid hydrolase. In the second pathway the sulfone is further oxidized to 2-(2′-hydroxyphenyl)benzene
sulfonate and then to HBP and sulfate by a sulfonic acid hydrolase. Experiments using benzene sulfonic acid suggest that the
sulfonic acid hydrolase is an induced enzyme.
Received: 8 June 1998 / Received revision: 1 October 1998 / Accepted: 2 October 1998 相似文献
16.
Bruce Richman 《Primates; journal of primatology》1978,19(3):569-581
Evidence is presented from recordings made from captive gelada monkeys (Theropithecus gelada) that these monkeys are capable of synchronizing the onsets of their own vocal sounds to the anticipated onsets of sounds
produced by other gelada voices. The possibility is discussed that in order to synchronize the onsets of their own sounds
to the anticipated onsets of sounds made by other voices, such gelada voices have to possess the ability to “figure out” the
tempo and rhythm of the vocal strings produced by the other voices and precisely control the timing of their own voices. It
is suggested that geladas do synchronize their voices by using precise temporal and rhythmical controls on the outputs of
their voices that are analogous to the temporal and rhythmical abilities humans use in many of the supra-segmental aspects
of speech. 相似文献
17.
Resistance to the toxic effects of reactive oxygen species produced by phagocytes and production of hydrolytic enzymes are
important aspects of Candida albicans virulence. In this report, we compared twelve C. albicans isolates for their in vitro capacity to resist oxidants—hydrogen peroxide, menadione and paraquat; and to produce hydrolytic
enzymes—phospholipase and protease. Different C. albicans isolates showed different degrees of resistance to oxidants as well as differences in production of hydrolytic enzymes. Resistance
to oxidative stress did not correlate with production of hydrolytic enzymes. This reinforces the view that C. albicans differentially regulates the expression of virulence factors in response to local environmental conditions. 相似文献
18.
J. D. Colvin 《International journal of primatology》1985,6(3):261-287
Several aspects of breeding-season relationships with mature females are described for free-ranging immature male rhesus monkeys (Macaca mulatta)on Cayo Santiago. At puberty, immature males are still groomed by mature females, as they were as infants, but no longer receive
active protection from females other than their mothers. A further, potentially beneficial, aspect of their associations with
females lies in the opportunities to observe closely the tactical social and sexual interactions of receptive females with
adult males. However, immature males themselves rarely copulate with females. Developmental constraints may explain the finding
that most females observed by immature males were relatives but that high-ranking males showed a particular preference for
adolescent relatives, whereas the preference of low-ranking males was for adult relatives. A further finding was that while
there was a tendency for immature males to devote a greater proportion of their total observation time to females that ranked
above their mothers than to those of inferior rank, these were also the females from which males received the most aggression,
while most of the females with which the males groomed or copulated were lower ranking than the males’ mothers. Of three hypotheses
concerning three possible types of social constraint which might account for such a finding, the data supported only one—that
particular levels of aggression within these relationships are compatible only with certain other elements (observations),
and not with others (grooming, copulation). 相似文献
19.
Previous research has shown that the qualities of nuptial gifts among nonhumans and marriage-related property transfers in
human societies such as bridewealth and dowry covary with aspects of mate quality. This article explores this issue for another
type of marriage-related property transfer: engagement rings. We obtained data on engagement ring costs and other variables
through a mail survey sent to recently married individuals living in the American Midwest. This article focuses on survey
responses regarding rings that were purchased by men acting alone and using only their own funds who then presented the rings
while making surprise proposals of marriage (n = 127). Men marrying younger women spent more on rings, as did men who earned more money and whose fiancées earned more money.
These findings suggest that the amounts spent on engagement rings, like bridewealth and dowry payments in other societies,
reflect aspects of both male and female mate quality. 相似文献
20.
Biotechnological production of flavours and fragrances 总被引:7,自引:0,他引:7
The biotechnological generation of natural aroma compounds is rapidly expanding. Aroma chemicals, such as vanillin, benzaldehyde
(bitter almond, cherry) and 4-(R)-decanolide (fruity–fatty) are marketed on a scale of several thousand tons per year. Their possible production by single-step
biotransformations, bioconversions and de novo synthesis using microorganisms, plant cells or isolated enzymes is shown. The
perspectives of bioprocesses for the oxifunctionalisation of lower terpenes by genetically modified organisms and economic
aspects are discussed.
Received: 27 May 1997 / Received revision: 25 September 1997 / Accepted: 28 September 1997 相似文献