2,474 research outputs found
Topology of spin meron pairs in coupled Ni/Fe/Co/Cu(001) disks
No full textThe meron is a special topological object that carries only one-half of the topological charge unit. In condensed matter physics, a spin meron corresponds to one-half of a spin skyrmion. As compared to the many fascinating topological properties of skyrmion materials, little is known of the properties of spin merons especially about their formation. It was confirmed only recently that hedgehog merons could exist in pairs with opposite helicities via a spin flux closure. However, it is unclear whether a single hedgehog meron could ever exist by pairing with another type of meron. Using element-resolved magnetic imaging measurements on epitaxial trilayer disks, we show that a spin meron with a full range of helicity, including the hedgehog meron, can be stabilized by pairing with another vortex meron with a fine tuning of the magnetic coupling between the two merons. Furthermore, the meron divergence is fully controlled by the polarity of the vortex meron, independent of the vortex helicity.National Science Foundation [DMR-1504568]; Future Materials Discovery Program through the National Research Foundation of Korea [2015M3D1A1070467]; Science Research Center Program through the National Research Foundation of Korea [2015R1A5A1009962]; Office of Science, Office of Basic Energy Sciences; US Department of Energy [DE-AC02-05CH11231]SCI(E)[email protected]
Testing equality: insanity, treatment refusal and the CRPD
No full textThe Convention on the Rights of Persons with Disabilities is considered to be a radical international treaty that affords persons with disability recognition and protection of equal rights in socio-cultural, political, medical and legal arenas. Drawing from the Convention's core principles of equality and non-discrimination, the High Commissioner for Human Rights and the Convention's Committee have called for a replacement of the insanity defence with a disability-neutral doctrine. The rationale is that retaining this special defence is, in itself, discriminatory, given its function is necessarily based on the presence of mental disability and the assumption that such disabilities impair capacity and reasoning. This article interrogates the rationale behind ‘abolitionist’ views, and asks whether equality necessarily means treating all persons identically regardless of capacity to reason about conduct.</p
Meron ground states of quantum Hall droplets
No full textWe argue that topological meron excitations, which are in a strong coupling phase ͑bound in pairs͒ in infinite quantum Hall ferromagnets, become deconfined in finite-size quantum Hall systems. Although effectively for larger systems meron energy grows with the size of the system, when gyromagnetic ratio is small meron becomes the lowest-lying state of a quantum Hall droplet. This comes as a consequence of the many-body correlations built in the meron construction that minimize the interaction energy. We demonstrate this by using mean-field ansatzes for meron wave function. The ansatzes will enable us to consider much larger system sizes than in the previous work ͓A. Petković and M. V. Milovanović, Phys. Rev. Lett. 98, 066808 ͑2007͔͒, where fractionalization into merons was introduced
Legal narratives as significant news sources about mental illness and violent crime
No full textMedia coverage about people affected by mental illness is an area of research that is extensively examined. Many scholars argue that the media depicts people with mental illness as inherently violent and dangerous within sensational narratives. These depictions are criticized for reinforcing the social stigma and disadvantages many of the mentally ill face. The media does, however, require news sources and, in the context of crime and mental illness, the courts are a significant source. Through qualitative content analysis of Australian newspaper articles, this research examines an under-researched and incompletely theorized area. In doing so, it demonstrates that media depictions of some mentally ill offenders reflect and heavily draw upon legal narratives and what is argued in court about these offenders in the context of criminal responsibility and legal insanity
Homeland and its use of bipolar disorder for sensationalist and dramatic effect
No full textWhen a lead character in a critically acclaimed and award-winning television programme is depicted as a proficient and meticulous heroine with a mental disorder, it is crucial to examine if this reflects a change in the media depiction of people with mental illness. This article employs framing analysis to examine the portrayal of lead CIA agent with bipolar disorder, Carrie Mathison, in Homeland. Although the show did initially associate competence, intellect and astuteness to this character, as it progressed, the framing decisions used for dramatic and sensational purposes ultimately presented Mathison within the usual stereotypical depictions: as impulsive, irrational, unpredictable, unstable, dangerous and disordered. Given the popularity of the show, responsible depictions should take priority over dramatic effect at the expense of a character with mental illness because sufferers may be deterred in speaking about their illness and seeking appropriate treatment if such negative themes persist.</p
Evaluating predominant causes of insanity in cases of drug-induced psychoses
No full textThe insanity defense operates on the basis that individuals who do not have the capacity to understand the consequences or wrongness of their action should not be held criminally responsible because there is a defect of reason. The defect must arise from a ‘disease of mind’ having internal causes. This raises questions about the way the law deals with externally caused defects of reason—such as drug-induced psychoses—because it depends on whether voluntary intoxication caused acute psychosis and ensuing insanity directly linked to voluntary intoxication; triggered or exacerbated an existing psychotic mental illness; or triggered a psychotic illness that was fixed and permanent due to chronic substance abuse but is independent of acute intoxication: a case of ‘settled insanity.’ The latter two conditions can form a sufficient basis for the defense. But can cognitive impairments arising from mental disorders be distinguished from those arising from substance abuse disorders? How are such distinctions made? This article uses an Australian case to illuminate the nuanced operations of the defense because a verdict of ‘not guilty because of mental impairment’ was reached even though the defendant had no prior history of mental illness and had consumed cocaine and methamphetamine prior to his killings. Evaluators should consider the predominant rather than precise cause of insanity in cases in which voluntary intoxication and mental illness are pertinent issues for the purposes of the defense
Depressed but not legally mentally impaired
No full textThis article examines the mental impairment (insanity) defense in the Australian state of Victoria and argues that the defense is successful only when offenders suffer from psychotic mental illnesses. This raises the question about how non-psychotic offenders are dealt with by the courts when they claim ‘mental impairment’ for serious acts of violence such as homicide, particularly when a relatively large number of perpetrators involved in homicide suffer from non-psychotic illnesses like depression. The analysis shows that depressive illnesses do not reach the threshold for mental impairment (legal insanity) such that they mitigate violent criminal behavior, although they can, arguably, diminish culpability. This article draws upon existing literature, qualitative analysis of two court cases and semi-structured interviews with four legal representatives to make its conclusion
Creation and annihilation of topological meron pairs in in-plane magnetized films
No full textMerons which are topologically equivalent to one-half of skyrmions can exist only in pairs or groups in two-dimensional (2D) ferromagnetic (FM) systems. The recent discovery of meron lattice in chiral magnet Co8Zn9Mn3 raises the immediate challenging question that whether a single meron pair, which is the most fundamental topological structure in any 2D meron systems, can be created and stabilized in a continuous FM film? Utilizing winding number conservation, we develop a new method to create and stabilize a single pair of merons in a continuous Py film by local vortex imprinting from a Co disk. By observing the created meron pair directly within a magnetic field, we determine its topological structure unambiguously and explore the topological effect in its creation and annihilation processes. Our work opens a pathway towards developing and controlling topological structures in general magnetic systems without the restriction of perpendicular anisotropy and Dzyaloshinskii–Moriya interaction. © 2019, The Author(s).TRU
Reevaluating Chlorotoxin Targets: Insights Into Glioblastoma Cell Migration and Neuropilin-1 Binding
No full text2025Glioblastoma (GBM) is an aggressive and rapidly progressing brain tumor with a poor prognosis, characterized by a median survival rate of 15 months. Current treatment options remain limited, highlighting the need for novel therapeutic approaches. Improving imaging techniques to better localize and characterize GBM is one such strategy. Chlorotoxin (Ctx), a 36-amino-acid residue polypeptide derived from Leiurus quinquestriatus scorpion venom, has shown selective binding to GBM cells, making it a promising candidate for diagnostic applications and improving tumor visualization. However, the molecular targets of Ctx are unclear, with Matrix Metalloproteinase-2 (MMP-2) and Neuropilin-1 (NRP-1) being the most studied candidates. Previous studies have identified the C-terminal region of Ctx as critical for inhibiting GBM cell migration. To explore this further, we designed C-terminal peptide fragments of Ctx with various disulfide bridge modifications, hypothesizing that they could more effectively inhibit U-87 MG migration than full-length Ctx. Wound-healing assay results revealed that P78 (Ctx residues 27–34) exhibited the strongest inhibition of U-87 MG migration compared to other peptides and full-length Ctx. To investigate the molecular targets of Ctx and its fragments, biophysical techniques were utilized such as nanoDifferential Scanning Fluorimetry (nanoDSF) and Surface Plasmon Resonance (SPR). These analyses revealed that Ctx and its C-terminal fragments exhibit weak binding to NRP-1 at high micromolar affinities.Additionally, an enzymatic inhibition assay showed that Ctx and its fragments do not inhibit MMP-2 catalytic activity. Furthermore, tetrapeptides were designed to assess their binding to NRP-1. All tetrapeptides displayed submicromolar
affinities for NRP-1, suggesting that the canonical CendR motif is not essential for NRP-1 binding. Overall, these findings highlight the potential of C-terminal Ctx fragments, particularly P78, as effective inhibitors of GBM cell migration. They
also provide new insights into the interactions of peptides with NRP-1, paving the way for further exploration of their therapeutic applications
Modelling the survival of bacteria in drylands: the advantage of being dormant
No full textWe introduce a simple mathematical model for the description of
`dormancy', a survival strategy used by some bacterial populations that
are intermittently exposed to external stress. We focus on the case of
the cyanobacterial crust in drylands, exposed to severe water shortage,
and compare the fate of ideal populations that are, respectively,
capable or incapable of becoming dormant. The results of the simple
model introduced here indicate that under a constant, even though low,
supply of water the dormant strategy does not provide any benefit and it
can, instead, decrease the chances of survival of the population. The
situation is reversed for highly intermittent external stress, due to
the presence of prolonged periods of dry conditions intermingled with
short periods of intense precipitation. In this case, dormancy allows
for the survival of the population during the dry periods. In contrast,
bacteria that are incapable of turning into a dormant state cannot
overcome the difficult times. The model also rationalizes why dormant
bacteria, such as those composing the cyanobacterial crust in the
desert, are extremely sensitive to other disturbances, such as trampling
cattle
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