17,688 research outputs found
Monopole Bubbling via String Theory
In this paper, we propose a string theory description of generic 't Hooft
defects in supersymmetric gauge theories. We show that
the space of supersymmetric ground states is given by the moduli space of
singular monopoles and that in this setting, Kronheimer's correspondence is
realized as T-duality. We conjecture that this brane configuration can be used
to study the full dynamics of monopole bubbling.Comment: 46 pages plus Appendi
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Metachronous Intraductal Papillary Neoplasm of the Bile Duct and Intraductal Papillary Mucinous Neoplasm of the Pancreas in a Patient Diagnosed With Mucinous Adenocarcinoma.
Intraductal papillary neoplasm of the bile duct (IPNB) is a rare biliary tumor, which shares some radiologic and histologic similarities with pancreatic intraductal papillary mucinous neoplasm (IPMN). IPNB is a recognized precursor lesion of invasive adenocarcinoma. We present a case of metachronous IPNB and IPMN lesions in a patient with mucinous adenocarcinoma of the pancreas who presented with jaundice and abdominal pain. The patient was treated with surgery and adjuvant chemotherapy
The String Landscape, the Swampland, and the Missing Corner
We give a brief overview of the string landscape and techniques used to
construct string compactifications. We then explain how this motivates the
notion of the swampland and review a number of conjectures that attempt to
characterize theories in the swampland. We also compare holography in the
context of superstrings with the similar, but much simpler case of topological
string theory. For topological strings, there is a direct definition of
topological gravity based on a sum over a "quantum gravitational foam." In this
context, holography is the statement of an identification between a gravity and
gauge theory, both of which are defined independently of one another. This
points to a missing corner in string dualities which suggests the search for a
direct definition of quantum theory of gravity rather than relying on its
strongly coupled holographic dual as an adequate substitute (Based on TASI 2017
lectures given by C. Vafa)
Towards validation of a new computerised test of goal neglect: preliminary evidence from clinical and neuroimaging pilot studies
Objective:
Goal neglect is a significant problem following brain injury, and is a target for rehabilitation. It is not yet known how neural activation might change to reflect rehabilitation gains. We developed a computerised multiple elements test (CMET), suitable for use in neuroimaging paradigms.
Design:
Pilot correlational study and event-related fMRI study.
Methods:
In Study 1, 18 adults with acquired brain injury were assessed using the CMET, other tests of goal neglect (Hotel Test; Modified Six Elements Test) and tests of reasoning. In Study 2, 12 healthy adults underwent fMRI, during which the CMET was administered under two conditions: self-generated switching and experimenter-prompted switching.
Results:
Among the clinical sample, CMET performance was positively correlated with both the Hotel Test (r = 0.675, p = 0.003) and the Modified Six Elements Test (r = 0.568, p = 0.014), but not with other clinical or demographic measures. In the healthy sample, fMRI demonstrated significant activation in rostro-lateral prefrontal cortex in the self-generated condition compared with the prompted condition (peak 40, 44, 4; ZE = 4.25, p(FWEcorr) = 0.026).
Conclusions:
These pilot studies provide preliminary evidence towards the validation of the CMET as a measure of goal neglect. Future studies will aim to further establish its psychometric properties, and determine optimum pre- and post-rehabilitation fMRI paradigms
A Bio-economic Model of a Shrimp Hatchery in the Mekong River Delta of Vietnam
Shrimp culture areas and production of the Mekong Delta cover about 60 percent of the total shrimp areas and production of Vietnam. Especially, the Delta contributes about 80 percent of the total shrimp production for export. Rapid development of the shrimp industry is raising a number of serious problems that need to be solved. Shrimp seed supply (post larvae production) plays an essential role in the shrimp industry and it is one of the most important constraints to the development of the shrimp industry in the Delta. The focus of this study is aimed at obtaining an improvement in both the profit per day and post larvae production of the shrimp hatchery in the Mekong River Delta of Vietnam. A Monte Carlo simulation approach was applied to develop a stochastic and dynamic bio-economic model of a shrimp hatchery in the Delta. Initial results and policy recommendations are based on the analysis of the hatchery system simulation using a forward recursion approach and by changing the most important assumptions.Shrimp hatchery, larval stage, system simulation modelling, Agricultural and Food Policy, Production Economics,
Collide and Conquer: Constraints on Simplified Dark Matter Models using Mono-X Collider Searches
The use of simplified models as a tool for interpreting dark matter collider
searches has become increasingly prevalent, and while early Run II results are
beginning to appear, we look to see what further information can be extracted
from the Run I dataset. We consider three `standard' simplified models that
couple quarks to fermionic singlet dark matter: an -channel vector mediator
with vector or axial-vector couplings, and a -channel scalar mediator. Upper
limits on the couplings are calculated and compared across three alternate
channels, namely mono-jet, mono- (leptonic) and mono- (hadronic). The
strongest limits are observed in the mono-jet channel, however the
computational simplicity and absence of significant -channel model width
effects in the mono-boson channels make these a straightforward and competitive
alternative. We also include a comparison with relic density and direct
detection constraints.Comment: 32 pages, 8 figures; v2: minor changes, conclusion unchanged, matches
published versio
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