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1.
During the last three decades the interest toward clinical application of magnetic and electromagnetic stimulation increased worldwide. Numerous publications have discussed the possibility of exogenous magnetic fields to initiate beneficial effects on various biological processes, which are of critical importance for healing of different injuries and pathologies. Today, magnetic and electromagnetic fields are increasingly utilized for the treatment of numerous musculoskeletal injuries and pathologies. For example, selected magnetic fields were reported to be beneficial in the treatment of musculoskeletal injuries and post-surgical, post traumatic and chronic wounds, reduction of edema, in the acceleration of pain and stress relief, and thus contribute to healing processes. The application of this modality could be facilitated by establishing the exact dosimetry of application and by searching for biophysical mechanisms of action, as well. It should be remembered that “not all magnets are equal”, therefore the specific medical problem requires a proper diagnostics, a selection of the magnetic field to be applied and a design of the appropriate protocol for treatment. The paper advised that every study and report should carefully explain both the medical problem and the parameters of the applied magnetic field and cautions against generalized statements like “Magnetic field does/does not cause biological response”.  相似文献   

2.
The use of magnetic fields (MFs), in general, and electromagnetic fields (EMFs), in specific, as therapeutic modalities is becoming very common. In the USA, EMFs are mostly used in orthopedics, followed by pain relief and the wound-healing arena. Even though a substantial literature exists worldwide, we are still lacking the accepted comprehensive mechanism(s) of action. In general, it is thought that the best therapeutic effects are achieved when the stimulation is applied directly to the target area. Since the beginning of this century, however, more and more evidence has been collected indicating that effects of the MF stimulation may also be observed at site(s) different from the site of application of the signal. A primary purpose of this paper is to propose a link between the systemic and direct effects. The functional units known as trigger points are discussed as possible “doors” allowing the stimulation to be delivered to the target tissue/organ. A second purpose is to suggest some possible modes of action.  相似文献   

3.
Summary Despite of decades of successful worldwide use of magnetic/electromagnetic field therapy, the answer to the question of possible mechanisms of action is still lacking. Scientific reports of successful therapeutic use of magnetic/electromagnetic fields are worldwide; however, our understanding of the underlying mechanism is limited. This paper presents a new hypothesis that therapeutic benefit of magnetic fields might result from effects that originated on the level of important systems in human body. It is known now that the life is an electromagnetic event in aqueous medium. Therefore, an appropriate choice of magnetic and/or electromagnetic field may be expected to initiate systemic changes that result in efficacious effects distant from the point of application. Observations of this phenomenon have been reported in at least two forms: (1) neutralization of the pain experience distant to the point of magnetic field exposure; and, (2) various alterations of T-lymphocytes in response to pain and to magnetic fields. Extrapolating these observations to the level of blood-vessel system, one might hypothesize that a “healthy” cell does not respond as readily to the applied fields as do abnormal cells (which are in a disease or injury state).  相似文献   

4.
The interest toward clinical application of magnetic and electromagnetic stimulation increases worldwide. Numerous publications discussed the possibility exogenous magnetic and electromagnetic fields to initiate effects on various biological processes, which are of critical importance for healing of different injuries and pathologies. Today, magnetic and electromagnetic fields are increasingly utilized for treatment of various musculoskeletal injuries and pathologies. For musculoskeletal injuries and post-surgical, post traumatic and chronic wounds, reduction of edema is a major therapeutic factor in the acceleration of pain and stress relief, and thus contribute to healing processes. Electromagnetic and magnetic fields appear to be unique in their safety during clinical use. The application of this new modality will be facilitated by searching for biophysical mechanisms of action as well as by establishing exact dosimetry of application. In that respect basic science research needs to be developed in parallel with clinical applications. Magnetotherapy provides a non-invasive, safe, and easy method to directly treat the site of injury, the source of pain and inflammation, and other types of injury. Unfortunately, there are many obstacles that magnetotherapy has to overcome—both from the mainstream medicine as well as from the manufacturers and distributors of magnetic devices. The physical principle of magnetism as well as the physiological bases for the use of magnetic field for tissue repair are subjects of this review.  相似文献   

5.
Summary Since IARC classified ELF magnetic field as Possibly Carcinogenic to Human the fear from 50/60 Hz magnetic field exposure had been increased to the state of public “panic”. Subsequently, environment quality preservation organizations increased their pressure on their government to adopt the “precautionary principle” and to reduce the allowable ELF Magnetic Field exposure to much lower values than are recommended by ICNIRP-1998. As an example the present Environmental Ministry in Israel recommendation is to lower the ELF Field exposure to 10 mG averaged over 24 h. As a result of this stringent exposure guideline imposed by the government, electrical engineers who are involved in the deployment and installation of large and medium electrical utilities, such as overhead power lines, transformers, UPS systems, electrical public transportation, switching stations, etc., are much more aware to the need to employ special measures and methods for reducing the magnetic fields that might be emitted from such utilities. There are few computer codes that are capable of analyzing with great accuracy magnetic and electric fields surrounding single phase and three phase electrical utilities in a 3-D system. The best presentations of the analysis results are by equi-value contours depicting electric and magnetic fields. This graphical presentation is a powerful design tool that enables better deployment and installation design aided to reduce the magnetic field emissions from high-power electrical utilities. This paper describes the various types of graphical presentations available for ELF field contours, the dependent and independent variants and parameters, magnetic field animation for optimization of power line installation and routing, and finally an example that demonstrates the usefulness of the graphical presentation tools.  相似文献   

6.
Epidemiological studies suggesting the possibility of harmful effects on human (specifically children’s leukaemia) due to long-term exposure to magnetic fields of extremely low frequency (e.g. 50/60 Hz) and relatively low values (i.e. over the microtesla range) have stirred high activity in the topic of magnetic field mitigation. To reduce these fields, it is common to use passive metal screens (e.g. plates made of aluminium or steel). To design them, effective and fast numerical computations are highly desirable. In this article, a method is presented, which computes various parameters of screens in a given shielding problem and yields magnetic field distribution and shielding factors. The method takes into consideration the 3D field distribution and is able to solve systems with large aspect ratios (thin thickness in comparison with its other dimensions); this is a common problem where other methods such as finite elements often experience difficulties. The presented method computes separately the field inside and outside the screens. Afterwards, the solutions are “stitched” together along the border of the subregions. Two practical examples are given of the developed numerical method.  相似文献   

7.
8.
The creation of protected conservation areas may result in protracted conflicts between stakeholders. In this study we examine the drivers of anthropogenic wildfire ignitions in the National Park of “los Alerces” (NPA) in Patagonia, Argentina. The NPA was established in 1937 to protect the native “andino-patagónico” forests from wildfires as well as preserving its scenic beauty and native flora and fauna. At the time of its creation state authorities prohibited all extractive human activities in the “intangible”—fully protected—“National Park” section, while other regulated extractive and ecotourism activities were allowed to continue in the “Natural Reserve” section in an effort to accommodate the historical entitlements of the displaced populations of “pobladores” (settlers) that had been living in the NPA for over a century. Here we interviewed the main stakeholder groups—“pobladores”, forest rangers and administrators, ecolodge owners and angler club members—to identify the drivers of wildfire ignitions in the park. Wildfires have been singled out by state authorities as the main threat to the NPA though considerable scientific uncertainty exists regarding their complex ecological effects. This study argues, based on the human and biophysical system data collected, that two conflicting cultural frames exist within the NPA that provide the necessary backdrop for understanding the drivers of wildfire ignitions. In turn, these findings raise puzzling dilemmas for the main theoretical approaches that have been used to inform and design conflict management strategies in protected conservation areas.  相似文献   

9.
Green Space Changes and Planning in the Capital Region of China   总被引:4,自引:0,他引:4  
Green space plays an important role in complex urban ecosystems and provides significant ecosystem services with environmental, aesthetic, recreational and economic benefits. Beijing is the capital city of China and has a large population of about 15.81 million. Construction of green spaces is an important part of sustainable development in Beijing. To attain the sustainable development of Beijing as a capital city, an international city, a historical cultural city, and a living amenity city, this article attempts to develop a comprehensive plan of green space development both at the municipal and regional levels. At the municipal level of Beijing, based on the study of green space changes, and taking physical geographic conditions and historical context into account, we propose to establish green barriers in the mountainous area, and plan a comprehensive green space pattern composed of one city, two rings, three networks, eight water areas, nine fields, and several patches in the plain area. At the regional level of the Capital Circle Region, integrating the characteristics and causes of main environmental issues, we design a macroscopic pattern—“barriers by mountains in the northwest,” “seaward open spaces in the southeast,” “grassland-forest-field-coast zones,” and “green-blue symphony”—for ecological restoration and green space construction. Finally, we discuss the principles necessary to implement green space planning considering adaptation to local conditions, composite function exploitation, interregional equity and integrated planning.  相似文献   

10.
In managing environmental problems, several countries have chosen the management by objectives (MBO) approach. This paper investigates how focus group participants from the Swedish environmental administration used metaphors to describe the mode of organization needed to attain environmental objectives. Such analysis can shed light on how an MBO system is perceived by actors and how it works in practice. Although the Swedish government intended to stimulate broad-based cooperation among many actors, participants often saw themselves as located at a certain “level,” i.e., “higher” or “lower,” in the MBO system—that is, their conceptions corresponded to a traditional, hierarchical interpretation of MBO. Prepositions such as “in” and “out” contributed to feelings of inclusion and exclusion on the part of MBO actors. However, horizontal metaphors merged with vertical ones, indicating ongoing competition for the right to interpret how the system of environmental objectives should best be managed. The paper concludes that any organization applying MBO could benefit from discussing alternate ways of talking and thinking about its constituent “levels.”  相似文献   

11.
Two frequent beliefs about rural environmental attitudes are examined conceptually and empirically: (1) the common conception that rural environmental concerns are expressed predominantly by wealthy community newcomers; and (2) the related position that long-time rural residents are hostile to the environmental cause. We argue conceptually, through the use of a 2×2 community matrix, that environmental attitudes are equally likely to be expressed by what we term “upper middle income newcomers,” “lower middle income newcomers,” “upper middle income locals,” and “lower middle income locals.” Empirically, we find that although wealthy newcomers express the strongest environmental attitudes in the community, their concerns represent only a small percentage of rural environmental attitudes consisting of respondents who make less than $40,000 a year in household income are over 40 years of age, possess less than a college education, and work in a nonprofessional occupation. This new category expresses environmental concerns at least equal to the rest of the community on three of four measures of environmental attitudes. The findings provide insight into the widespread and cross-sectional nature of rural environmental concern. The implication is that environmental groups will find significant sources of political support in rural communities, provided they craft their environmental message in a language consistent with rural attitudes and values. Things are gettin' bad fast. Easterners and environmentalists comin' down here from the big cities are tryin' to turn our way of life completely upside down. A western US rancher quoted in Krakauer (1991)  相似文献   

12.
In 1988 I published a paper “Electromagnetic fields—a new ecological factor” (Markov 1988). There was no internet and very few cell phones were available. It was not even fear from the hazard of the power lines. However, I want to cite the beginning of this paper: “The contemporary conditions of life put man in dependence of the complex of physical influences on the environment and in the first place—of the electromagnetic fields. The rapid development of science and technology has resulted in the introduction of many new devices and technologies in industry, agriculture, and everyday life. On the other hand, during their phylogenetic and ontogenic development, the living organisms are continuously exposed to the influence of different biotic and abiotic factors. The physical factors are included in the first group, and the entire evolution of life is connected with an adaptation to the action of these factors.” Could I repeat this statement nearly a quarter of century later? Sure, I will. The only difference would be that I will speak not only for electromagnetic fields, but for green-house effects, global warming, volcano eruption, and radiation disasters. I would also discuss the noise and vibration to which people are exposed from early days to the very end of their life traveling with private vehicles or public transport.  相似文献   

13.
There is a continuing debate about the proper role of analytical (positivist) science in natural resource decision making. Two diametrically opposed views are evident, arguing for and against a more extended role for scientific information. The debate takes on a different complexion if one recognizes that certain kinds of problem, referred to here as “wicked” or “trans-science” problems, may not be amenable to the analytical process. Indeed, the mistaken application of analytical methods to trans-science problems may not only be a waste of time and money but also serve to hinder policy development. Since many environmental issues are trans-science in nature, then it follows that alternatives to analytical science need to be developed. In this article, the issues involved in the debate are clarified by examining the impact of the use of analytical methods in a particular case, the spruce budworm controversy in New Brunswick. The article ends with some suggestions about a “holistic” approach to the problem.  相似文献   

14.
Benefits-based management seeks to provide recreation benefits for recreation participants by managing the physical environments in which recreation occurs. This study investigates the relationship between benefits desired by visitors and the physical, social, and managerial characteristics of settings that facilitate realization of recreation benefits. Data such as perceived benefits from recreation experiences, setting attributes that significantly influenced perceived benefits, and sociodemographic variables were collected from 376 visitors to Sorak-san National Park in the eastern part of the Korean peninsula. Cluster analysis was used to group visitors' desired benefits into 12 domains: relationship with nature/scenery, escaping pressure, learning about nature, family togetherness, introspection, exploration, autonomy/achievement, being with friends, leading others, skills/learning, risk taking, and meeting/observing new people. Multiple regression was used to link benefit domains with the characteristics of settings. The social attribute of recreation settings was linked to eight of the ten benefit domains. There were two statistically strong multiple regression correlations: (1) between domain of “relationship with nature /scenery” and the attributes “forest/water,”“attractive nature,” and “facility/maintenance” and (2) between the domain of “escaping pressure” and the attributes “attractive nature” and “social.” The results of this study are useful to managers in their efforts to provide recreation opportunities for visitors to achieve beneficial outcomes.  相似文献   

15.
The term moral considerability refers to the question of whether a being or set of beings is worthy of moral consideration. Moral considerability is most readily afforded to those beings that demonstrate the clearest relationship to rational humans, though many have also argued for and against the moral considerability of species, ecosystems, and “lesser” animals. Among these arguments there are at least two positions: “environmentalist” positions that tend to emphasize the systemic relations between species, and “liberationist” positions that tend to emphasize the attributes or welfare of a particular individual organism. Already, this classic conflict provides for some challenging theoretical clashes between environmentalists and animal liberationists. The question of moral considerability is complicated, however, by recent developments in genetic engineering. Some animals, like pigs and fish, have been genetically modified by humans to grow organs that can then be transplanted into humans. If environmental arguments for the moral consideration of species are correct, then we are released from our obligations to morally consider those animals that we have genetically modified, since they are by their nature always an “invader species.” If, instead, the welfare of the animal is of penultimate importance, then there is a case for strengthening the moral considerability of GM animals over “naturally-occurring” animals, since they bear a closer relationship to humans. This would appear to be an intractable problem, a “bad marriage,” as Mark Sagoff once proposed. This paper argues that the case of invasive transgenic animals exposes weaknesses in this classic conflict, and particularly, in the framing of this conflict. To remedy this framing problem, this paper argues for a reconceptualization of the term “moral considerability,” instead urging a strong distinction between moral considerability, moral relevance, and moral significance.  相似文献   

16.
Norton argues on pragmatic “Deweyan” grounds that we should cease to ask scientists for value neutral definitions of “sustainability,” developed independently of moral and social values, to guide our environmental policy making debates. “Sustainability,” like human “health,” is a normative concept from the start—one that cannot be meaningfully developed by scientists or economists without input by all the stake holders affected. While I endorse Norton’s approach, I question his apparent presumption that concern for sustainability for the future is at odds with and ought to trump concern for enhancement in the present of public opportunities to access the goods nature represents. I argue that the two are not separable in practice. I argue for Passmore’s position that unless we take care to enhance equitable access to the good and services nature represents in the present, we cannot succeed in promoting sustainability for future generations.  相似文献   

17.
Several attempts to conceptualize farm animal welfare have been criticized for diverging reasons, among them often the failure to incorporate the public concern and opinion. This paper’s objective is to develop a conception of farm animal welfare that starts from the public’s perception and integrates the opinion of different stakeholder representatives, thus following a fork-to-farm approach. Four qualitative citizen focus group discussions were used to develop a quantitative questionnaire, which has been completed by a representative sample of Flemish citizens (n = 459). Exploratory and confirmatory factor analyses were applied to develop a conception of farm animal welfare starting from an extended list of aspects that relate to animal production and associate with farm animal welfare in the public’s perception. In depth interviews with stakeholder representatives were used to match and adapt the structure of the animal welfare conception model. The resulting conception revealed seven dimensions grouped in two different levels. Three dimensions were animal-based: “Suffering and Stress,” “Ability to Engage in Natural Behavior,” and “Animal Health.” Four dimensions were resource-based: “Housing and Barn climate,” “Transport and Slaughter,” “Feed and Water,” and “Human-Animal Relationship.” This conception is distinct from earlier attempts since it is based on public perceptions; it addresses the opinion of different stakeholders, and it distinguishes empirically between animal-based and resource-based dimensions in the conceptualization of farm animal welfare. The relevancy of a popular definition is supported by the present demand oriented economy, in which animal welfare is a non-trade concern, and mainly left to the market where consumers still mainly act as individuals who calculate and weigh pros and cons.  相似文献   

18.
This study assessed coastal erosion vulnerability along a 90-km sector, which included both erosional and accretionary beaches, and different levels of human occupation. Two aerial photogrammetric flights were used to reconstruct coastal evolution between 1977 and 1999. During this period, extensive accretion was recorded updrift of human structures at harbors and ports, e.g., Scoglitti (105.6 m), Donnalucata (52.8 m), and Pozzallo (94.6 m). Conversely, erosion was recorded in downdrift areas, with maximum values at Modica Stream mouth (63.8 m) and Point Castellazzo (35.2 m). Assessments were subsequently divided into four categories ranging from “high erosion” to “accretion.” Several sources were examined to assess human activities and land use. The latter was mapped and divided into four categories, ranging from “very high” to “no capital” land use. Subsequently, coastal erosion vulnerability was assessed by combining land use categories with recorded coastline behavior. Results showed “very high” to “high” vulnerability along 5.8% and 16.6%, respectively, of the littoral, while 20.9% and 56.7%, respectively, was found to exhibit “medium” and “low/very low” vulnerability. A very good agreement between predicted coastal vulnerability and coastal trend had been observed over recent years. Furthermore, several human structures and activities are located within the “imminent collapse zone (ICZ)” which reached maximum values of 17.5 m at Modica Stream and 13.5 m at Point Braccetto.  相似文献   

19.
The history of the establishment and management philosophies of the mainland Portuguese Protected Areas was reconstructed through the use of written records and oral history interviews. The objectives were to review the main philosophies in the creation and management of these areas, to assess the influence of international PA models, to compare the Portuguese case with other European and international literature concerning PAs and to discuss the value of the oral history in this research. As main results, it was found that the initial management model of “Wilderness (or Yellowstone)” was replaced by the “new paradigm” of PAs when the democracy was re-established. Changes in the management philosophies within this “new paradigm” were also identified, which resulted in the transition of a “Landscape” to a “Nature conservation” model. After the establishment of the Natura 2000 network, the “Biodiversity conservation” model prevailed. It was also found that the initiative for the establishment of most PAs came from the government, although there were few cases of creation due to the action of NGOs and municipalities. Finally, oral history interviews enabled the addition of information to the literature review, but also provided more insight and detail to this history.  相似文献   

20.
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