356 research outputs found

    Selected Hydrogeologic and Water-quality Data from Jones Beach Island, Long Island, New York

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    A data-collection site was instrumented on Jones Beach Island, a barrier island south of Long Island, N.Y., to study local freshwater/ saltwater relations in the shallow ground-water system. A geologic test boring revealed about 88 feet of well-sorted glacial outwash sand above about 15 feet of Gardiners Clay, which directly overlies silty sand of the Magothy Formation. Tidal effects on water levels in Great South Bay, the upper glacial aquifer, and the Magothy aquifer were observed and quantified with a tidal gage in the bay and analog water-level recorders in the wells.Chloride concentrations in the upper Magothy aquifer were higher than expected--about 270 mg/L (milligrams per liter), and those in the upper glacial aquifer were 17,000 to 19,000 mg/L, about the same as in Great South Bay. Estimates of pressure and freshwater equivalent heads indicate that, at the data-collection site, freshwater is discharging upward from the Magothy aquifer into the salty upper glacial aquifer, but dilution by this freshwater is undetectable. The reason for the elevated chloride concentration in the Magothy aquifer cannot be determined from available hydrogeologic information

    Autofluorescence in eleocytes of some earthworm species.

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    Immunocompetent cells of earthworms, coelomocytes, comprise adherent amoebocytes and granular eleocytes (chloragocytes). Both cell populations can be expelled via dorsal pores of adult earthworms by exposure to an electric current (4.5 V) for 1 min. Analysis by phase contrast/fluorescence microscopy and flow cytometry demonstrated that eleocyte population of several species exhibits a strong autofluorescence. A high percentage (11-35%) of autofluorescent eleocytes was recorded in Allolobophora chlorotica, Dendrodrilus rubidus, Eisenia fetida, and Octolasion sp. (O. cyaneum, O. tyrtaeum tyrtaeum and O. tyrtaeum lacteum). In contrast, autofluorescent coelomocytes were exceptionally scarce (less than 1%) in representative Aporrectodea sp. (A. caliginosa and A. longa) and Lumbricus sp. (L. castaneus, L. festivus, L. rubellus, L. terrestris). Thus, this paper for the first time describes profound intrinsic fluorescence of eleocytes in some--but not all--earthworm species. The function (if any) and inter-species differences of the autofluorescent coelomocytes still remain elusive

    Menstrual Cycle and the Temporal Discrimination Threshold

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    The temporal discrimination threshold (TDT) is a proposed pre-clinical biomarker (endophenotype) for adult onset isolated focal dystonia (AOIFD). Age- and sex-related effects on temporal discrimination demonstrate that women, before the age of 40 years, have faster temporal discrimination than men but their TDTs worsen with age at almost three times the rate of men. Thus after 40 years the TDT in women is progressively worse than in men. AOIFD is an increasingly female-predominant disorder after the age of 40; it is not clear whether this age-related sexually-dimorphic difference observed for both the TDT and sex ratio at disease onset in AOIFD is a hormonal or chromosomal effect. The aim of this study was to examine temporal discrimination at weekly intervals during two consecutive menstrual cycles in 14 healthy female volunteers to determine whether physiological hormonal changes affected temporal discrimination. We observed no significant differences in weekly temporal discrimination threshold values during the menstrual cycles and no significant correlation with the menstrual cycle stage. This observed stability of temporal discrimination during cyclical hormonal change raises interesting questions concerning the age-related sexually-dimorphic decline observed in temporal discrimination. Our findings pave the way for future studies exploring potential pathomechanisms for this age-related deterioration

    A Comparison of Stimulus Presentation Methods in Temporal Discrimination Testing

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    The temporal discrimination threshold (TDT) is the shortest time interval at which an individual detects two stimuli to be asynchronous (normal  =  30-50 ms). It has been shown to be abnormal in patients with disorders affecting the basal ganglia including adult onset idiopathic focal dystonia (AOIFD). Up to 97% of patients have an abnormal TDT with age- and sex-related penetrance in unaffected relatives, demonstrating an autosomal dominant inheritance pattern. These findings support the use of the TDT as a pre-clinical biomarker for AOIFD. The usual stimulus presentation method involves the presentation of progressively asynchronous stimuli; when three sequential stimuli are reported asynchronous is taken as a participant\u27s TDT. To investigate the robustness of the \u27staircase\u27 method of presentation, we introduced a method of randomised presentation order to explore any potential \u27learning effect\u27 that may be associated with this existing method. The aim of this study was to investigate differences in temporal discrimination using two methods of stimulus presentation. Thirty healthy volunteers were recruited to the study (mean age 33.73  ±  3.4 years). Visual and tactile TDT testing using a staircase and randomised method of presentation order was carried out in a single session. There was a strong relationship between the staircase and random method for TDT values. This observed consistency between testing methods suggests that the existing experimental approach is a robust method of recording an individual\u27s TDT. In addition, our newly devised randomised paradigm is a reproducible and more efficient method for data acquisition in the clinic setting. However, the two presentation methods yield different absolute TDT results and either of the two methods should be used uniformly in all participants in any one particular study. doi: 10.1088/1361-6579/38/2/N5

    Disrupted Superior Collicular Activity May Reveal Crvical Dystonia Disease Pathomechanisms

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    Cervical dystonia is a common neurological movement disorder characterised by muscle contractions causing abnormal movements and postures afecting the head and neck. The neural networks underpinning this condition are incompletely understood. While animal models suggest a role for the superior colliculus in its pathophysiology, this link has yet to be established in humans. The present experiment was designed to test the hypothesis that disrupted superior collicular processing is evident in afected patients and in relatives harbouring a disease-specifc endophenotype (abnormal temporal discrimination). The study participants were 16 cervical dystonia patients, 16 unafected frst-degree relatives with abnormal temporal discrimination, 16 unafected frst-degree relatives with normal temporal discrimination and 16 healthy controls. The response of participant’s superior colliculi to looming stimuli was assessed by functional magnetic resonance imaging. Cervical dystonia patients and relatives with abnormal temporal discrimination demonstrated (i) signifcantly reduced superior collicular activation for whole brain and region of interest analysis; (ii) a statistically signifcant negative correlation between temporal discrimination threshold and superior collicular peak values. Our results support the hypothesis that disrupted superior collicular processing is involved in the pathogenesis of cervical dystonia. These fndings, which align with animal models of cervical dystonia, shed new light on pathomechanisms in humans

    Disrupted Superior Collicular Activity May Reveal Cervical Dystonia Disease Pathomechanisms

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    Cervical dystonia is a common neurological movement disorder characterised by muscle contractions causing abnormal movements and postures affecting the head and neck. The neural networks underpinning this condition are incompletely understood. While animal models suggest a role for the superior colliculus in its pathophysiology, this link has yet to be established in humans. The present experiment was designed to test the hypothesis that disrupted superior collicular processing is evident in affected patients and in relatives harbouring a disease-specific endophenotype (abnormal temporal discrimination). The study participants were 16 cervical dystonia patients, 16 unaffected first-degree relatives with abnormal temporal discrimination, 16 unaffected first-degree relatives with normal temporal discrimination and 16 healthy controls. The response of participant’s superior colliculi to looming stimuli was assessed by functional magnetic resonance imaging. Cervical dystonia patients and relatives with abnormal temporal discrimination demonstrated (i) significantly reduced superior collicular activation for whole brain and region of interest analysis; (ii) a statistically significant negative correlation between temporal discrimination threshold and superior collicular peak values. Our results support the hypothesis that disrupted superior collicular processing is involved in the pathogenesis of cervical dystonia. These findings, which align with animal models of cervical dystonia, shed new light on pathomechanisms in humans

    Measurement & Analysis of the Temporal Discrimination Threshold Applied to Cervical Dystonia

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    The temporal discrimination threshold (TDT) is the shortest time interval at which an observer can discriminate two sequential stimuli as being asynchronous (typically 30-50 ms). It has been shown to be abnormal (prolonged) in neurological disorders, including cervical dystonia, a phenotype of adult onset idiopathic isolated focal dystonia. The TDT is a quantitative measure of the ability to perceive rapid changes in the environment and is considered indicative of the behavior of the visual neurons in the superior colliculus, a key node in covert attentional orienting. This article sets out methods for measuring the TDT (including two hardware options and two modes of stimuli presentation). We also explore two approaches of data analysis and TDT calculation. The application of the assessment of temporal discrimination to the understanding of the pathogenesis of cervical dystonia and adult onset idiopathic isolated focal dystonia is also discussed

    The Grizzly, November 30, 1979

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    College Costs To Skyrocket • Committee Explores Campus Problems • Audiovisual Services Relocated in Myrin • USGA Notes • Letters to the Editor • Roving Reporter: Iranian Crisis • Portrait of a Professor: Dr. John Wickersham • JDB - Full of Surprises • Vonnegut\u27s \u27Jailbird\u27: Life of Walter Starbuck • Pilgrim To Speak On Economy • Cagers Open 79-80 Campaign With Victory • Gridders Win Finale With Shut-Out • Garner Races To 68th In Nation • Sports Profile: Rick Morris • Pool Records Sethttps://digitalcommons.ursinus.edu/grizzlynews/1029/thumbnail.jp

    Disrupted Superior Collicular Activity May Reveal Cervical Dystonia Disease Pathomechanisms

    Get PDF
    Cervical dystonia is a common neurological movement disorder characterised by muscle contractions causing abnormal movements and postures affecting the head and neck. The neural networks underpinning this condition are incompletely understood. While animal models suggest a role for the superior colliculus in its pathophysiology, this link has yet to be established in humans. The present experiment was designed to test the hypothesis that disrupted superior collicular processing is evident in affected patients and in relatives harbouring a disease-specific endophenotype (abnormal temporal discrimination). The study participants were 16 cervical dystonia patients, 16 unaffected first-degree relatives with abnormal temporal discrimination, 16 unaffected first-degree relatives with normal temporal discrimination and 16 healthy controls. The response of participant’s superior colliculi to looming stimuli was assessed by functional magnetic resonance imaging. Cervical dystonia patients and relatives with abnormal temporal discrimination demonstrated (i) significantly reduced superior collicular activation for whole brain and region of interest analysis; (ii) a statistically significant negative correlation between temporal discrimination threshold and superior collicular peak values. Our results support the hypothesis that disrupted superior collicular processing is involved in the pathogenesis of cervical dystonia. These findings, which align with animal models of cervical dystonia, shed new light on pathomechanisms in humans
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