786 research outputs found
A study of tagging methods for the sea cucumber Cucumaria frondosa in the waters off Maine
The sea cucumber fishery in waters off Maine is developing and has recently experienced great increases in landings, corresponding to expanding export markets. Between 1994 and 1996, reported landings ranged from one to three million pounds (Fig. 1). In 1999, reported landings were over eight million pounds and rose to over nine million in 2000 (Feindel1). Like other developing fisheries, we have little information about the biology and ecology of the sea cucumber off Maine, limited data on the fishery, and little knowledge about the key life history processes that characterize its population dynamics. Therefore, we have a limited understanding of the current status of the resource and the impacts the fishery may have on the stock
A Manifest Revolution: Access and Specialization in Legal Education and Practice
The new consciousness of legal ignorance stems from the perception that law has become more complex. It is not simply a case of there being more rules or regulations, rather, the meaning and function of law have become more complicated. Intuitions of justice, the content of natural law, have been qualitatively displaced by positivist law-making. Legal dilemmas are less easily framed in terms of moral imperatives as law becomes more site-specific, more embedded in material circumstance and social histories. The law has become more complex because the society it regulates has become more complex. More decisions need to be made because more choices exist, and in this sense, law attempts to structure a society that is increasingly defined – though this logic exceeds the very notion of definition – by its variance with itself, defined not by what it is but by the possibilities of what it can be or, alternatively, by what it is not. Only in rhetoric can the organization we call society be reduced to one set of values or to a single overarching principle of social cohesion – if indeed cohesion is easily distinguished from tension. The forces effecting the articulation and construction of the law resist any simple or holistic characterization of legal knowledge. The decomposition of the unity of legal knowledge has meant that its content no longer submits to any one end; it is no longer evident to say for whom or for what it is, or should be, composed. This predicament does not, however, release us from the need to decide and re-decide these questions. It is in view of these issues that a new perspective on legal education and legal practice is offered. While critics of legal institutions have identified both the problem of wider access to legal knowledge and the increasing specialization of legal knowledge, rare is it that these cuts are made by the same sword. Typically, proponents of access to the law oppose the concentration of special knowledge in the hands of an elite whose access to \u27legal institutions is primarily based on socio-economic privilege. The crisis of legal knowledge has painted a picture that hints at even greater elitism: the knowledge lawyers require to function effectively in society is due to become even more removed from the civilian denominator of common sense. The authors contend in this comment that the aims of wider access and of specialization can be viewed in complementary terms
A Manifest Revolution: Access and Specialization in Legal Education and Practice
The new consciousness of legal ignorance stems from the perception that law has become more complex. It is not simply a case of there being more rules or regulations, rather, the meaning and function of law have become more complicated. Intuitions of justice, the content of natural law, have been qualitatively displaced by positivist law-making. Legal dilemmas are less easily framed in terms of moral imperatives as law becomes more site-specific, more embedded in material circumstance and social histories. The law has become more complex because the society it regulates has become more complex. More decisions need to be made because more choices exist, and in this sense, law attempts to structure a society that is increasingly defined – though this logic exceeds the very notion of definition – by its variance with itself, defined not by what it is but by the possibilities of what it can be or, alternatively, by what it is not. Only in rhetoric can the organization we call society be reduced to one set of values or to a single overarching principle of social cohesion – if indeed cohesion is easily distinguished from tension. The forces effecting the articulation and construction of the law resist any simple or holistic characterization of legal knowledge. The decomposition of the unity of legal knowledge has meant that its content no longer submits to any one end; it is no longer evident to say for whom or for what it is, or should be, composed. This predicament does not, however, release us from the need to decide and re-decide these questions. It is in view of these issues that a new perspective on legal education and legal practice is offered. While critics of legal institutions have identified both the problem of wider access to legal knowledge and the increasing specialization of legal knowledge, rare is it that these cuts are made by the same sword. Typically, proponents of access to the law oppose the concentration of special knowledge in the hands of an elite whose access to \u27legal institutions is primarily based on socio-economic privilege. The crisis of legal knowledge has painted a picture that hints at even greater elitism: the knowledge lawyers require to function effectively in society is due to become even more removed from the civilian denominator of common sense. The authors contend in this comment that the aims of wider access and of specialization can be viewed in complementary terms
William Osler at McGill University: the baby professor and his early contributions to neurosurgery
Journal ArticleBetween 1870 and 1884, as both a medical student and a member of the faculty, Sir William Osler performed approximately 1000 postmortem examinations at McGill University in Montreal. He conducted 786 of these examinations during his 7 years (1877-1884) of service as a pathologist at the M were carefully recorded and catalogued either by him or by those who compiled the Pathological Report of the Hospital. Included in this material are many early descriptions of neurosurgical disease. Osler used this information for subsequent teaching in both Philadelphia and Baltimore. Osler's early and lifelong special interest in diseases of the nervous system not only led him to make seminal observations but also served to initiate his influence and relationships with the emerging leaders in neurology and neurosurgery
The influence of host and non-host crops on the rhizobial population of the root rhizosphere
Non-Peer ReviewedField pea (Pisum sativum), a new crop to the Dark Brown and Black Chernozemic Soil Zones of Saskatchewan, forms a symbiosis with Rhizobium leguminosarum biovar viceae. This rhizobium is not native to the region, yet numbers in excess of 10^4 g-1 soil have been observed several years after a single inoculated field pea crop was grown. Modified immunoblot and ELISA techniques utilizing strain-specific polyclonal antibodies were used to monitor the environmental effect of host and non-host crop on rhizobial populations. The proportion of soil rhizobia able to nodulate pea differed between a competitive and poorly competitive isolate. Numbers of rhizobia declined over time in non-rhizosphere soil and increased in the presence of host plant. Both isolates maintained or increased soil populations from the initial level in the presence of certain non-host plants. The proportion of rhizobia available to nodulate a pea root increased more for the poorly competitive isolate in the presence of host and non-host root systems but did not reach the level of the highly competitive isolate
Combined rTMS/fMRI studies: An overlooked resource in animal models
Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive neuromodulation technique, which has brain network-level effects in healthy individuals and is also used to treat many neurological and psychiatric conditions in which brain connectivity is believed to be abnormal. Despite the fact that rTMS is being used in a clinical setting and animal studies are increasingly identifying potential cellular and molecular mechanisms, little is known about how these mechanisms relate to clinical changes. This knowledge gap is amplified by non-overlapping approaches used in preclinical and clinical rTMS studies: preclinical studies are mostly invasive, using cellular and molecular approaches, while clinical studies are non-invasive, including functional magnetic resonance imaging (fMRI), TMS electroencephalography (EEG), positron emission tomography (PET), and behavioral measures. A non-invasive method is therefore needed in rodents to link our understanding of cellular and molecular changes to functional connectivity changes that are clinically relevant. fMRI is the technique of choice for examining both short and long term functional connectivity changes in large-scale networks and is becoming increasingly popular in animal research because of its high translatability, but, to date, there have been no reports of animal rTMS studies using this technique. This review summarizes the main studies combining different rTMS protocols with fMRI in humans, in both healthy and patient populations, providing a foundation for the design of equivalent studies in animals. We discuss the challenges of combining these two methods in animals and highlight considerations important for acquiring clinically-relevant information from combined rTMS/fMRI studies in animals. We believe that combining rTMS and fMRI in animal models will generate new knowledge in the following ways: functional connectivity changes can be explored in greater detail through complementary invasive procedures, clarifying mechanism and improving the therapeutic application of rTMS, as well as improving interpretation of fMRI data. And, in a more general context, a robust comparative approach will refine the use of animal models of specific neuropsychiatric conditions
Frequency-specific effects of low-intensity rTMS can persist for up to 2 weeks post-stimulation: A longitudinal rs-fMRI/MRS study in rats
Background
Evidence suggests that repetitive transcranial magnetic stimulation (rTMS), a non-invasive neuromodulation technique, alters resting brain activity. Despite anecdotal evidence that rTMS effects wear off, there are no reports of longitudinal studies, even in humans, mapping the therapeutic duration of rTMS effects.
Objective
Here, we investigated the longitudinal effects of repeated low-intensity rTMS (LI-rTMS) on healthy rodent resting-state networks (RSNs) using resting-state functional MRI (rs-fMRI) and on sensorimotor cortical neurometabolite levels using proton magnetic resonance spectroscopy (MRS).
Methods
Sprague-Dawley rats received 10 min LI-rTMS daily for 15 days (10 Hz or 1 Hz stimulation, n=9 per group). MRI data were acquired at baseline, after seven days and after 14 days of daily stimulation and at two more timepoints up to three weeks post-cessation of daily stimulation.
Results
10 Hz stimulation increased RSN connectivity and GABA, glutamine, and glutamate levels. 1 Hz stimulation had opposite but subtler effects, resulting in decreased RSN connectivity and glutamine levels. The induced changes decreased to baseline levels within seven days following stimulation cessation in the 10 Hz group but were sustained for at least 14 days in the 1 Hz group.
Conclusion
Overall, our study provides evidence of long-term frequency-specific effects of LI-rTMS. Additionally, the transient connectivity changes following 10 Hz stimulation suggest that current treatment protocols involving this frequency may require ongoing “top-up” stimulation sessions to maintain therapeutic effects
Optimization of hatchery culture of the sea scallop, Placopecten Magellanicus (Gmelin,1791) : dietary lipid quality and fatty acid requirements
Different species of live algal cultures varying broadly in essential fatty acid content - eicosapentaenoic acid (EPA; 20:5n-3), docosahexaenoic acid (DHA; 22:6n-3), and arachidonic acid (ARA; 20:4n-6) - were used in exploratory experiments to evaluate the impact of dietary lipid quality on broodstock conditioning and larval culture of the sea scallop (Placopecten magellanicus). Egg biochemical composition was relatively stable when diets were fed to animals in a partially conditioned state, but varied more for wild eggs compared to lab-conditioned animals. When diet treatments were initiated earlier in a second experiment, differences among the fatty acid composition of gonad samples were more apparent. -- In larval feeding trials, fatty acids in neutral lipids, and to lesser extent phospholipids, of larvae reflected the composition of the algae they were fed. Câ‚‚â‚€ and Câ‚‚â‚‚ PUFA were preferentially accumulated, particularly DHA which plays a specific structural role in Pectinids. Growth results suggest increasing dietary ARA, or possibly 22:5n-6. -- Last, variability in lipid quality was examined in aging batch cultures of a strain of Pavlova sp. (CCMP459). Lipid, mainly TAG, as a proportion of dry weight, more than doubled over the experimental period. As cultures aged, the (n-3)/(n-6) series fatty acid ratio was reduced. By controlling algal harvest strategies or culture conditions, the biochemical composition of algae may be optimized to best meet the nutritional needs of a particular bivalve species or developmental stage
Coronary sinus sampling of cytokines after heart transplantation: Evidence for macrophage activation and interleukin-4 production within the graft
AbstractObjectives. This study was undertaken to evaluate the organ-specific release of cytokines after heart transplantation and to assess any correlation with transplant rejection. This cytokine profile should document the relative activation of mononuclear cell subsets within the graft.Background. Up to 60% of mononuclear cell infiltrating the cardiac allograft during rejection are macrophages, but their rote is undetermined. The T lymphocytes are activated, but the activity of specific T cell subsets is not known. We sought to assess for the first time in humans the in vivo activation of mononuclear cell subsets by measuring coronary sinus cytokine levels after heart transplantation.Methods. Palred superior vena cava and coronary sinus serum samples were assayed for interkeukin (IL)-2, IL-4 and IL-6, soluble IL-2 receptors, tumor necrosis factor-alpha and neopterin in 10 patients at the time of 40 routine endomyocardial biopsy procedures. All cytokine measurements were made by using enzyme-linked immunosorbent assay; neopterin was measured by using radioimmunoassy.Results. Interleukin-2 levels were not detectable (<0.8 U/ml) in either the superior vena cava or the coronary sinus in the presence or absence of rejection. Interleukin-2 receptor levels were uniformly elevated to 1,283 U/ml in the superior vena cava and to 1,232 U/ml in the coronary sinus, with no correlation with rejection severity. Interleukin-4 levels were consistently higher in coronary sinus serum than in peripheral blood (229 vs. 61 pg/ml, p < O.0005), but there was no relation with rejection. Interleukin-6 levels were higher in the coronary sinus than in me superior vena cava (200 vs. 120 pg/mi, p < 0.05). Tumor necrosis factor-alpha showed consistently elevated levels in coronary sinus serum (68 vs. 17 pg/ml, p < 0.0005), with no relation with rejection. Neopterin, which is produced only by activated macro-phages, was also consistently elevated in the coronary sinus (2.5 vs. 2.2 nmol, p = 0.08).Conclusions. The cardiac allograft is a major source of cyto-kines after heart transplantation. The cytokine profile allows the activity of subsets of the mononuclear cell infiltrate to be investigated. Elevated coronary sinus activity of the macrophage specific metabolite neopterin suggests macrophage activation within the allograft. This possibility is supported by elevated coronary sinus levels of tumor necrosis factor-alpha and IL-6. The T lymphocytes are activated, as evidenced by high soluble IL-2 receptor levels, but IL-2 production was suppressed by conventional immunosup-pressive therapy. Coronary sinus IL-4 levels represent T helper-2 cell activation within the graft despite immunosuppression. We could find no temporal relation between the coronary sinus or superior vena cava cytokine concentration or profile and severity of rejection on concurrent biopsy studies
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