308 research outputs found
Ecological effects of highways on coastal wetlands, Atlantic coast region
A literature review of past and on-going research and activities of the principal investigators is the basis for evaluating environmental effects of highways in wetlands. Values of wetl8,$1ds are discussed briefly. Physical. biological and chemical impacts are associated with highway construction. operation and maintenance. Environmental impacts are scaled in terms of magnitude and duration and mitigating measures are identified. The foregoing are summarized in matrices. The report further identifies further research which is needed to design highway projects with environmental aspects in mind
The meandering instability of a viscous thread
A viscous thread falling from a nozzle onto a surface exhibits the famous
rope-coiling effect, in which the thread buckles to form loops. If the surface
is replaced by a belt moving with speed , the rotational symmetry of the
buckling instability is broken and a wealth of interesting states are observed
[See S. Chiu-Webster and J. R. Lister, J. Fluid Mech., {\bf 569}, 89 (2006)].
We experimentally studied this "fluid mechanical sewing machine" in a new, more
precise apparatus. As is reduced, the steady catenary thread bifurcates
into a meandering state in which the thread displacements are only transverse
to the motion of the belt. We measured the amplitude and frequency of
the meandering close to the bifurcation. For smaller , single-frequency
meandering bifurcates to a two-frequency "figure eight" state, which contains a
significant component and parallel as well as transverse
displacements. This eventually reverts to single-frequency coiling at still
smaller . More complex, highly hysteretic states with additional frequencies
are observed for larger nozzle heights. We propose to understand this zoology
in terms of the generic amplitude equations appropriate for resonant
interactions between two oscillatory modes with frequencies and
. The form of the amplitude equations captures both the axisymmetry of
the U=0 coiling state and the symmetry-breaking effects induced by the moving
belt.Comment: 12 pages, 9 figures, revised, resubmitted to Physical Review
A role for pathogenic autoantibodies in small fiber neuropathy?
The immune system has a role in neuropathic pain which includes autoimmune mechanisms (e.g., autoantibodies). Clinical studies have identified a number of conditions where neuropathic pain is common and that are associated with autoantibodies targeting antigens within the nervous system. Interestingly sensory symptoms can be relieved with immunotherapies or plasma exchange, suggesting that pain in these patients is antibody-mediated. Recent preclinical studies have directly addressed this. For example, passive transfer of CASPR2 autoantibodies from patients cause increased pain sensitivity and enhanced sensory neuron excitability in mice confirming pathogenicity and demonstrating that patient autoantibodies are a mechanism to cause neuropathic pain. Small fiber neuropathy (SFN) exclusively affects small sensory fibers (typically nociceptors) and is characterized by severe neuropathic pain. Known causes include diabetes, B12 deficiency and rare variants in sodium channel genes, although around 50% of cases are idiopathic. SFN is associated with autoimmune conditions such as Sjorgenâs syndrome, Sarcoidosis and Celiac disease and immunotherapy in the form of Intravenous immunoglobulin (IVIG) has proved an effective treatment. Autoantibodies have been identified and, in some cases, passive transfer of SFN patient IgG in mice can recapitulate neuropathic pain-like behavior. Here we will discuss clinical and preclinical data relating to the idea that pathogenic autoantibodies contribute to SNF. We discuss putative pathogenic antibodies, cellular targets and the molecular mechanisms by which they cause sensory neuron damage and the development of neuropathic pain. Finally, we will comment on future directions which may provide further insights into the mechanisms underlying SFN in patients
Bemiparin versus low dose aspirin for management of recurrent early pregnancy losses due to antiphospholipd antibody syndrome
Does cannabis use predict psychometric schizotypy via aberrant salience?
Cannabis can induce acute psychotic symptoms in healthy individuals and exacerbate pre-existing psychotic symptoms in patients with schizophrenia. Inappropriate salience allocation is hypothesised to be central to the association between dopamine dysregulation and psychotic symptoms. This study examined whether cannabis use is associated with self-reported salience dysfunction and schizotypal symptoms in a non-clinical population. 910 University students completed the following questionnaire battery: the cannabis experience questionnaire modified version (CEQmv); schizotypal personality questionnaire (SPQ); community assessment of psychic experience (CAPE); aberrant salience inventory (ASI). Mediation analysis was used to test whether aberrant salience mediated the relationship between cannabis use and schizotypal traits. Both frequent cannabis consumption during the previous year and ASI score predicted variation across selected positive and disorganised SPQ subscales. However, for the SPQ subscales âideas of referenceâ and âodd beliefsâ, mediation analysis revealed that with the addition of ASI score as a mediating variable, current cannabis use no longer predicted scores on these subscales. Similarly, cannabis use frequency predicted higher total SPQ as well as specific Positive and Disorganised subscale scores, but ASI score as a mediating variable removed the significant predictive relationship between frequent cannabis use and âodd beliefsâ, âideas of referenceâ, âunusual perceptual experiencesâ, âodd speechâ, and total SPQ scores. In summary, cannabis use was associated with increased psychometric schizotypy and aberrant salience. Using self-report measures in a non-clinical population, the cannabis-related increase in selected positive and disorganised SPQ subscale scores was shown to be, at least in part, mediated by disturbance in salience processing mechanisms
Neurostructural and neurophysiological correlates of multiple sclerosis physical fatigue: systematic review and meta-analysis of cross-sectional studies
Fatigue is one of the most debilitating symptoms for people with multiple sclerosis (PwMS). By consolidating a diverse and conflicting evidence-base, this systematic review and meta-analysis aimed to gain new insights into the neurobiology of MS fatigue. MEDLINE, ProQuest, CINAHL, Web of Science databases and grey literature were searched using Medical Subject Headings. Eligible studies compared neuroimaging and neurophysiological data between people experiencing high (MS-HF) versus low (MS-LF) levels of perceived MS fatigue, as defined by validated fatigue questionnaire cut-points. Data were available from 66 studies, with 46 used for meta-analyses. Neuroimaging studies revealed lower volumetric measures in MS-HF versus MS-LF for whole brain (Â22.74 ml; 95% CI: -37.72 to -7.76 ml; p = 0.003), grey matter (Â18.81 ml; 95% CI: Â29.60 to Â8.03 ml; p < 0.001), putamen (Â0.40 ml; 95% CI: Â0.69 to Â0.10 ml; p = 0.008) and acumbens (Â0.09 ml; 95% CI: Â0.15 to Â0.03 ml; p = 0.003) and a higher volume of T1-weighted hypointense lesions (1.10 ml; 95% CI: 0.47 to 1.73 ml; p < 0.001). Neurophysiological data showed reduced lower-limb maximum voluntary force production (Â19.23 N; 95% CI: Â35.93 to Â2.53 N; p = 0.02) and an attenuation of upper-limb (Â5.77%; 95% CI:Â8.61 to Â2.93%; p < 0.0001) and lower-limb (Â2.16%; 95% CI:Â4.24 to Â0.07%; p = 0.04) skeletal muscle voluntary activation, accompanied by more pronounced upper-limb fatigability (Â5.61%; 95% CI: -9.57 to -1.65%; p = 0.006) in MS-HF versus MS-LF. Results suggest that MS fatigue is characterised by greater cortico-subcortical grey matter atrophy and neural lesions, accompanied by neurophysiological decrements, which include reduced strength and voluntary activation. Prospero registration Prospero registration number: CRD4201601793
Social Preferences and the Efficiency of Bilateral Exchange
Under what conditions do social preferences, such as altruism or a concern for fair outcomes, generate efficient trade? I analyze theoretically a simple bilateral exchange game: Each player sequentially takes an action that reduces his own material payoff but increases the other playerâs. Each playerâs preferences may depend on both his/her own material payoff and the other playerâs. I identify necessary conditions and sufficient conditions on the playersâ preferences for the outcome of their interaction to be Pareto efficient. The results have implications for interpreting the rotten kid theorem, gift exchange in the laboratory, and gift exchange in the field
Immune or genetic-mediated disruption of CASPR2 causes pain hypersensitivity due to enhanced primary afferent excitability
Human autoantibodies to contactin-associated protein-like 2 (CASPR2) are often associated with neuropathic pain, and CASPR2 mutations have been linked to autism spectrum disorders, in which sensory dysfunction is increasingly recognized. Human CASPR2 autoantibodies, when injected into mice, were peripherally restricted and resulted in mechanical pain-related hypersensitivity in the absence of neural injury. We therefore investigated the mechanism by which CASPR2 modulates nociceptive function. Mice lacking CASPR2 (Cntnap2 ) demonstrated enhanced pain-related hypersensitivity to noxious mechanical stimuli, heat, and algogens. Both primary afferent excitability and subsequent nociceptive transmission within the dorsal horn were increased in Cntnap2 mice. Either immune or genetic-mediated ablation of CASPR2 enhanced the excitability of DRG neurons in a cell-autonomous fashion through regulation of Kv1 channel expression at the soma membrane. This is the first example of passive transfer of an autoimmune peripheral neuropathic pain disorder and demonstrates that CASPR2 has a key role in regulating cell-intrinsic dorsal root ganglion (DRG) neuron excitability
A Case for Humans-in-the-Loop: Decisions in the Presence of Erroneous Algorithmic Scores
The increased use of algorithmic predictions in sensitive domains has been
accompanied by both enthusiasm and concern. To understand the opportunities and
risks of these technologies, it is key to study how experts alter their
decisions when using such tools. In this paper, we study the adoption of an
algorithmic tool used to assist child maltreatment hotline screening decisions.
We focus on the question: Are humans capable of identifying cases in which the
machine is wrong, and of overriding those recommendations? We first show that
humans do alter their behavior when the tool is deployed. Then, we show that
humans are less likely to adhere to the machine's recommendation when the score
displayed is an incorrect estimate of risk, even when overriding the
recommendation requires supervisory approval. These results highlight the risks
of full automation and the importance of designing decision pipelines that
provide humans with autonomy.Comment: Accepted at ACM Conference on Human Factors in Computing Systems (ACM
CHI), 202
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