4,423 research outputs found
A retrospective study of pyometra at five RSPCA hospitals in the United Kingdom: 1,728 cases from 2006-2011
A retrospective cross-sectional study was used to analyse pyometra cases at five RSPCA
Animal Hospitals across the UK from 2006 to 2011. A total of 1728 cases of pyometra
were recovered from a female dog outpatient caseload of 78,469 animals, giving a total
prevalence of 2.2 per cent over the study period. There was an annual increase in the
incidence of pyometra within the population, while elective ovariohysterectomy caseload has
declined. There were variations in breed and age at presentation. Bullmastiffs (P<0.0001),
golden retrievers (P=0.001) and dogue de Bordeaux (P=0.008) were over-represented in the
pyometra population when compared with the female dog outpatient caseload. Mean age
at presentation was 7.7 years. Some breeds presented at a significantly lower age, including
dogue de Bordeaux (mean age 3.3 years) and bullmastiffs (mean age 5.4 years), while
others presented as older dogs, including Yorkshire terriers (mean age 9.4 years) and border
collies (mean age 10.3 years). Surgical mortality rate at the Greater Manchester Animal
Hospital was 3.2 per cent. Pyometra is of significant welfare concern, and also has cost
implications, particularly in charity practice. These results serve to highlight this condition
so that future change in charity practice caseload can be anticipated and strategies can be
directed to improve animal welfare
Intraoperative Organ Motion Models with an Ensemble of Conditional Generative Adversarial Networks
In this paper, we describe how a patient-specific, ultrasound-probe-induced
prostate motion model can be directly generated from a single preoperative MR
image. Our motion model allows for sampling from the conditional distribution
of dense displacement fields, is encoded by a generative neural network
conditioned on a medical image, and accepts random noise as additional input.
The generative network is trained by a minimax optimisation with a second
discriminative neural network, tasked to distinguish generated samples from
training motion data. In this work, we propose that 1) jointly optimising a
third conditioning neural network that pre-processes the input image, can
effectively extract patient-specific features for conditioning; and 2)
combining multiple generative models trained separately with heuristically
pre-disjointed training data sets can adequately mitigate the problem of mode
collapse. Trained with diagnostic T2-weighted MR images from 143 real patients
and 73,216 3D dense displacement fields from finite element simulations of
intraoperative prostate motion due to transrectal ultrasound probe pressure,
the proposed models produced physically-plausible patient-specific motion of
prostate glands. The ability to capture biomechanically simulated motion was
evaluated using two errors representing generalisability and specificity of the
model. The median values, calculated from a 10-fold cross-validation, were
2.8+/-0.3 mm and 1.7+/-0.1 mm, respectively. We conclude that the introduced
approach demonstrates the feasibility of applying state-of-the-art machine
learning algorithms to generate organ motion models from patient images, and
shows significant promise for future research.Comment: Accepted to MICCAI 201
Phenomenological Study of Fathersâ Parental Alienation Experiences
AbstractHigh-conflict divorce and resulting parental alienation (PA) impact both the children and the parent who has been the target of PA. This situation has been found to cause mental health issues and unhealthy coping skills in children. The purpose of this phenomenological study was to explore the lived experiences of nonresidential fathers who were alienated from their children in the context of a high-conflict separation or divorce. This study was rooted in Bowlbyâs attachment theory. Data were collected from interviews with 10 adult participants. The software program Quirkos was used to review the data and discern thematic patterns and correlate the themes. Themes identified in the data where legal issues, physical ailments, mental health consequences, and financial consequences. Better understanding of the perspectives of fathers experienced PA increases awareness of the sequelae of high-conflict divorce. Such awareness can lead to positive social change by helping generate an understanding of what fathers may experience in high-conflict separation or divorce when the relationship with their children is strained or lost during high-conflict separation or divorce. The increased understanding from this study allows clinical professionals to target interventions and the legal system to address issues of PA in divorce proceedings, helping to create better outcomes for parents and children. This awareness allows clinical professionals and the legal system to address issues of PA in high-conflict divorces, helping to create better outcomes for parents and children
Adversarial Deformation Regularization for Training Image Registration Neural Networks
We describe an adversarial learning approach to constrain convolutional
neural network training for image registration, replacing heuristic smoothness
measures of displacement fields often used in these tasks. Using
minimally-invasive prostate cancer intervention as an example application, we
demonstrate the feasibility of utilizing biomechanical simulations to
regularize a weakly-supervised anatomical-label-driven registration network for
aligning pre-procedural magnetic resonance (MR) and 3D intra-procedural
transrectal ultrasound (TRUS) images. A discriminator network is optimized to
distinguish the registration-predicted displacement fields from the motion data
simulated by finite element analysis. During training, the registration network
simultaneously aims to maximize similarity between anatomical labels that
drives image alignment and to minimize an adversarial generator loss that
measures divergence between the predicted- and simulated deformation. The
end-to-end trained network enables efficient and fully-automated registration
that only requires an MR and TRUS image pair as input, without anatomical
labels or simulated data during inference. 108 pairs of labelled MR and TRUS
images from 76 prostate cancer patients and 71,500 nonlinear finite-element
simulations from 143 different patients were used for this study. We show that,
with only gland segmentation as training labels, the proposed method can help
predict physically plausible deformation without any other smoothness penalty.
Based on cross-validation experiments using 834 pairs of independent validation
landmarks, the proposed adversarial-regularized registration achieved a target
registration error of 6.3 mm that is significantly lower than those from
several other regularization methods.Comment: Accepted to MICCAI 201
Label-driven weakly-supervised learning for multimodal deformable image registration
Spatially aligning medical images from different modalities remains a
challenging task, especially for intraoperative applications that require fast
and robust algorithms. We propose a weakly-supervised, label-driven formulation
for learning 3D voxel correspondence from higher-level label correspondence,
thereby bypassing classical intensity-based image similarity measures. During
training, a convolutional neural network is optimised by outputting a dense
displacement field (DDF) that warps a set of available anatomical labels from
the moving image to match their corresponding counterparts in the fixed image.
These label pairs, including solid organs, ducts, vessels, point landmarks and
other ad hoc structures, are only required at training time and can be
spatially aligned by minimising a cross-entropy function of the warped moving
label and the fixed label. During inference, the trained network takes a new
image pair to predict an optimal DDF, resulting in a fully-automatic,
label-free, real-time and deformable registration. For interventional
applications where large global transformation prevails, we also propose a
neural network architecture to jointly optimise the global- and local
displacements. Experiment results are presented based on cross-validating
registrations of 111 pairs of T2-weighted magnetic resonance images and 3D
transrectal ultrasound images from prostate cancer patients with a total of
over 4000 anatomical labels, yielding a median target registration error of 4.2
mm on landmark centroids and a median Dice of 0.88 on prostate glands.Comment: Accepted to ISBI 201
Comparison of intestinal bacterial communities in asymptomatic and diseased Asian seabass (Lates calcarifer) with chronic enteritis and mixed bacterial infections
Asian seabass (Lates calcarifer) is a major aquaculture food fish species in Singapore. Farming of this species is increasingly threatened by frequent outbreaks of infectious diseases, resulting in mortality exceeding 50â70%. In this study, we investigated the comparative gut bacterial microbiota using 16S rRNA metasequencing between asymptomatic and diseased juvenile fish collected during a disease outbreak soon after stocking. Mild to severe chronic granulomatous enteritis was observed histopathologically in both asymptomatic and diseased fish. Kidneys of diseased fish tested PCR positive for the âbig bellyâ novel Vibrio spp., Streptococcus iniae and Vibrio harveyi. These bacteria were also readily detected by PCR in water samples corresponding to tanks fish were sampled from. Potentially beneficial microbes that promote gut health such as Firmicutes, Bacteroidota and Actinobacteriota were the dominant phyla in the intestinal microbiota of asymptomatic fish. Moreover, the bacteria with probiotic potential such as Lactobacillus only presented in asymptomatic fish, and Weissella was unique and prevalent (47.59%) in asymptomatic fish during the recovery phase of the disease outbreak, making them candidate biomarkers for monitoring health status of L. calcarifer. Conversely, diseased fish showed reduced diversity of their gut microbiome, with high abundance of members of the phylum Proteobacteria. Vibrio was the most dominant genus (87.3%) and Streptococcus iniae was only detected in diseased fish. These findings provide a baseline study for understanding changes in intestinal microbiota in newly stocked fish with mixed bacterial infection, biomarker assisted health monitoring, and future host-derived probiotics screening in L. calcarifer
Coloring Hypergraphs Induced by Dynamic Point Sets and Bottomless Rectangles
We consider a coloring problem on dynamic, one-dimensional point sets: points
appearing and disappearing on a line at given times. We wish to color them with
k colors so that at any time, any sequence of p(k) consecutive points, for some
function p, contains at least one point of each color.
We prove that no such function p(k) exists in general. However, in the
restricted case in which points appear gradually, but never disappear, we give
a coloring algorithm guaranteeing the property at any time with p(k)=3k-2. This
can be interpreted as coloring point sets in R^2 with k colors such that any
bottomless rectangle containing at least 3k-2 points contains at least one
point of each color. Here a bottomless rectangle is an axis-aligned rectangle
whose bottom edge is below the lowest point of the set. For this problem, we
also prove a lower bound p(k)>ck, where c>1.67. Hence for every k there exists
a point set, every k-coloring of which is such that there exists a bottomless
rectangle containing ck points and missing at least one of the k colors.
Chen et al. (2009) proved that no such function exists in the case of
general axis-aligned rectangles. Our result also complements recent results
from Keszegh and Palvolgyi on cover-decomposability of octants (2011, 2012).Comment: A preliminary version was presented by a subset of the authors to the
European Workshop on Computational Geometry, held in Assisi (Italy) on March
19-21, 201
Scotland Registry for Ankylosing Spondylitis (SIRAS) â Protocol
Funding SIRAS was funded by unrestricted grants from Pfizer and AbbVie. The project was reviewed by both companies, during the award process, for Scientific merit, to ensure that the design did not compromise patient safety, and to assess the global regulatory implications and any impact on regulatory strategy.Publisher PD
Tunneling Ionization Rates from Arbitrary Potential Wells
We present a practical numerical technique for calculating tunneling
ionization rates from arbitrary 1-D potential wells in the presence of a linear
external potential by determining the widths of the resonances in the spectral
density, rho(E), adiabatically connected to the field-free bound states. While
this technique applies to more general external potentials, we focus on the
ionization of electrons from atoms and molecules by DC electric fields, as this
has an important and immediate impact on the understanding of the multiphoton
ionization of molecules in strong laser fields.Comment: 13 pages, 7 figures, LaTe
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