5,158 research outputs found

    Why pair? Evidence of aggregative mating in a socially monogamous marine fish (Siganus doliatus, Siganidae)

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    © 2015 The Authors. Many species live in stable pairs, usually to breed and raise offspring together, but this cannot be assumed. Establishing whether pairing is based on mating, or an alternative cooperative advantage, can be difficult, especially where species show no obvious sexual dimorphism and where the act of reproduction itself is difficult to observe. In the tropical marine fishes known as rabbitfish (Siganidae), half of extant species live in socially monogamous, territorial pairs. It has been assumed that partnerships are for mating, but the reproductive mode of pairing rabbitfish is currently unconfirmed. Using passive acoustic telemetry to track movements of fishes belonging to one such species (Siganus doliatus), we provide the first evidence that paired adult fish undertake highly synchronized migrations with multiple conspecifics on a monthly cycle. All tagged individuals migrated along the same route in three consecutive months and were absent from home territories for 2–3 days just after the new moon. The timing and directionality of migrations suggest that S. doliatus may form spawning aggregations, offering the potential for exposure to multiple reproductive partners. The finding raises fundamental questions about the basis of pairing, mate choice and partnership longevity in this family

    A Generative-Discriminative Basis Learning Framework to Predict Clinical Severity from Resting State Functional MRI Data

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    We propose a matrix factorization technique that decomposes the resting state fMRI (rs-fMRI) correlation matrices for a patient population into a sparse set of representative subnetworks, as modeled by rank one outer products. The subnetworks are combined using patient specific non-negative coefficients; these coefficients are also used to model, and subsequently predict the clinical severity of a given patient via a linear regression. Our generative-discriminative framework is able to exploit the structure of rs-fMRI correlation matrices to capture group level effects, while simultaneously accounting for patient variability. We employ ten fold cross validation to demonstrate the predictive power of our model on a cohort of fifty eight patients diagnosed with Autism Spectrum Disorder. Our method outperforms classical semi-supervised frameworks, which perform dimensionality reduction on the correlation features followed by non-linear regression to predict the clinical scores

    Consistency of probabilistic classifier trees

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    Conditions during adulthood affect cohort-specific reproductive success in an Arctic-nesting goose population

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    This is the final version of the article. Available from the publisher via the DOI in this record.Variation in fitness between individuals in populations may be attributed to differing environmental conditions experienced among birth (or hatch) years (i.e., between cohorts). In this study, we tested whether cohort fitness could also be explained by environmental conditions experienced in years post-hatch, using 736 lifelong resighting histories of Greenland white-fronted geese (Anser albifrons flavirostris) marked in their first winter. Specifically, we tested whether variation in age at first successful reproduction, the size of the first successful brood and the proportion of successful breeders by cohort was explained by environmental conditions experienced on breeding areas in west Greenland during hatch year, those in adulthood prior to successful reproduction and those in the year of successful reproduction, using North Atlantic Oscillation indices as proxies for environmental conditions during these periods. Fifty-nine (8%) of all marked birds reproduced successfully (i.e., were observed on wintering areas with young) only once in their lifetime and 15 (2%) reproduced successfully twice or thrice. Variation in age at first successful reproduction was explained by the environmental conditions experienced during adulthood in the years prior to successful reproduction. Birds bred earliest (mean age 4) when environmental conditions were 'good' prior to the year of successful reproduction. Conversely, birds successfully reproduced at older ages (mean age 7) if they experienced adverse conditions prior to the year of successful reproduction. Hatch year conditions and an interaction between those experienced prior to and during the year of successful reproduction explained less (marginally significant) variation in age at first successful reproduction. Environmental conditions did not explain variation in the size of the first successful brood or the proportion of successful breeders. These findings show that conditions during adulthood prior to the year of successful reproduction are most important in determining the age at first successful reproduction in Greenland white-fronted geese. Very few birds bred successfully at all (most only once), which suggests that May environmental conditions on breeding areas have cohort effects that influence lifetime (and not just annual) reproductive success.This research was funded through a joint PhD studentship from the Wildfowl & Wetlands Trust and the University of Exeter, and undertaken by MD Weegman. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript

    FMRI resting slow fluctuations correlate with the activity of fast cortico-cortical physiological connections

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    Recording of slow spontaneous fluctuations at rest using functional magnetic resonance imaging (fMRI) allows distinct long-range cortical networks to be identified. The neuronal basis of connectivity as assessed by resting-state fMRI still needs to be fully clarified, considering that these signals are an indirect measure of neuronal activity, reflecting slow local variations in de-oxyhaemoglobin concentration. Here, we combined fMRI with multifocal transcranial magnetic stimulation (TMS), a technique that allows the investigation of the causal neurophysiological interactions occurring in specific cortico-cortical connections. We investigated whether the physiological properties of parieto-frontal circuits mapped with short-latency multifocal TMS at rest may have some relationship with the resting-state fMRI measures of specific resting-state functional networks (RSNs). Results showed that the activity of fast cortico-cortical physiological interactions occurring in the millisecond range correlated selectively with the coupling of fMRI slow oscillations within the same cortical areas that form part of the dorsal attention network, i.e., the attention system believed to be involved in reorientation of attention. We conclude that resting-state fMRI ongoing slow fluctuations likely reflect the interaction of underlying physiological cortico-cortical connections

    Determining the Role of Surgery in Diagnosis and Treatment of Primary CNS Lymphoma

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    Introduction: Primary central nervous system lymphoma (PCNSL) is a rare entity typically treated with a combination of chemotherapy and radiation. The role of surgery is controversial, and biopsy may be non-definitive or injurious. We review our series of stereotactic and excisional biopsy as well as surgical debulking of PCNSL to quantify overall risk and benefits. Methods: Patients with biopsy-confirmed intracranial PCNSL were identified from a large singlecenter academic institution between 2012-2018. Preoperative factors and perioperative outcomes were retrospectively reviewed. Results: A total of 61 cases of PCNSL were identified. Most patients presented with confusion (23.0%), weakness/paralysis (19.7%), and gait disturbance (18.0%). 1.6% were incidentally identified. HIV status was positive in 8.2% of cases. CSF cytology was positive for malignancy in 33.3% of applicable cases. Of all procedures, 44.3% were needle biopsy, 27.9% were open excisional biopsies, and 27.9% were surgical debulking procedures. Prior biopsy had been performed in 9.8%, of which 83.3% (5/6) were positive for PCNSL. Intraoperative frozen pathology failed to illicit a definitive diagnosis in 39.3% of cases despite adequate sampling. Stereotactic biopsies did not demonstrate an increased risk of non-diagnostic frozen pathology compared to open excisional biopsy. Intraoperative complications, 30-day mortality, and long-term survival was not associated with open vs. stereotactic biopsy. Discussion: Biopsy of PCNSL carries a moderate surgical risk that should not be discounted, particularly in the setting of previously diagnosed PCNSL or with evidence of malignancy in CSF cytology. Early initiation of chemotherapy continues to be the mainstay of long-term response and control

    Ventral Hernia Repairs: 10 year Single Institution Review at Thomas Jefferson University Hospital

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    Abstract Background Definitive repair of recurrent ventral hernias using abdominal wall reconstruction techniques is an essential tool in the armentarium for general and plastic surgeons. Ramirez 1 et al describes the “component separation” technique to mobilize the rectus-abdominus internal oblique and external oblique flap to correct the defect. The recurrence rate of incisional hernias increases to 20% after gastric bypass or extensive weight loss.2 The incidence of ventral hernias after failed recurrent hernia repair increases to 40%.3 It has been reported that utilizing the sliding myofascial flap repair technique, the recurrence rate was reduced to 8.5%.4 Materials and Methods This retrospective institutional study reviews 10 years of myofascial flap reconstruction 1996-2006 at TJUH. Several techniques and prosthetic materials (alloderm, permacol, vicryl, composix) were used in our institutional review by multiple surgeons in this time period. Our goal is to identify risk factors (i.e. smoking, diabetes, obesity, size of defect, peripheral vascular disease, enterocutaneous fistula, infection) that predict or categorize patients that are at increased risk for failure of primary repair, measure the complication rates (i.e. infection, recurrence, seroma, hematoma) and evaluate the techniques and long term effectiveness of several prosthetic materials. Results Three thousand twenty ventral hernia repairs were performed at TJUH between 1996 and 2006. Two thousand three hundred eighty three approximated the rectus abdominus primarily and of these 645 utilized a component separation technique. The recurrence rate for component separations was 18.5% and 83% for primary repairs. The average follow up was 5.49 years. Statistically significant risk factors (p\u3c0.05) for recurrence were obesity (BMI\u3e30 kg/m2), age\u3e65 years, male gender, preoperative infection and postoperative seroma. Conclusion Myofascial flaps are a safe, reliable therapy for recurrent ventral hernias that addresses the population of patients that have failed conventional primary closure and reduce the recurrence rates greater than 40 percent to 18.5 percent in the carefully selected patient population

    Dictionary Learning and Sparse Coding-based Denoising for High-Resolution Task Functional Connectivity MRI Analysis

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    We propose a novel denoising framework for task functional Magnetic Resonance Imaging (tfMRI) data to delineate the high-resolution spatial pattern of the brain functional connectivity via dictionary learning and sparse coding (DLSC). In order to address the limitations of the unsupervised DLSC-based fMRI studies, we utilize the prior knowledge of task paradigm in the learning step to train a data-driven dictionary and to model the sparse representation. We apply the proposed DLSC-based method to Human Connectome Project (HCP) motor tfMRI dataset. Studies on the functional connectivity of cerebrocerebellar circuits in somatomotor networks show that the DLSC-based denoising framework can significantly improve the prominent connectivity patterns, in comparison to the temporal non-local means (tNLM)-based denoising method as well as the case without denoising, which is consistent and neuroscientifically meaningful within motor area. The promising results show that the proposed method can provide an important foundation for the high-resolution functional connectivity analysis, and provide a better approach for fMRI preprocessing.Comment: 8 pages, 3 figures, MLMI201

    The effect of rapid response teams on end-of-life care: A retrospective chart review

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    R apid response teams (RRTs) were designed to assess and treat deteriorating ward patients. The aim of RRTs is to decrease the number of cardiac arrests, intensive care unit (ICU) transfers and inhospital mortality. These goals have been met with variable success in the literature, with some prospective cohort studies reporting reductions in cardiac arrests (1-4). However, these results were not replicated in the large, multicentre, cluster randomized controlled Medical Early Response Intervention and Therapy (MERIT) trial (5). The MERIT trial suggested that there was an association with RRTs and an increase in do-not-resuscitate orders (6,7). Further studies have also documented RRT involvement in end-of-life (EOL) care (8-10). To support EOL care, our institution implemented a hospital-wide policy and associated preprinted order set known as the PhysicianOrdered Spectrum of Treatment (POST) form. The POST form acted as an extension of a 'do not resuscitate' status. The form engaged health care providers in conversations with patients and families regarding life-sustaining interventions such as cardiopulmonary resuscitation, intubation, defibrillation, ICU transfer, antibiotics, blood products or intravenous lines The premise of our study was that hospitalized patients are in fragile condition and, although restorative therapies are often the goal, there are patients who do not want or who would not benefit from aggressive resuscitative measures. As 'first responders' for critically ill ward patients, RRTs have the opportunity to recognize and treat patients who would benefit from EOL care. We sought to characterize the effect of RRT EOL discussions on EOL care. We also characterized the proportion of patients seen by RRTs with EOL care issues. Finally, we examined how the introduction of a hospital-wide EOL preprinted order set influenced EOL discussions and EOL care. Methods The present study was a single-centre, retrospective chart review conducted at the Hamilton Health Sciences Hamilton General Hospital BACkgRound: A subset of critically ill patients have end-of-life (EOL) goals that are unclear. Rapid response teams (RRTs) may aid in the identification of these patients and the delivery of their EOL care. oBJeCtives: To characterize the impact of RRT discussion on EOL care, and to examine how a preprinted order (PPO) set for EOL care influenced EOL discussions and outcomes. Methods: A single-centre retrospective chart review of all RRT calls (January 2009 to December 2010) was performed. The effect of RRT EOL discussions and the effect of a hospital-wide PPO set on EOL care was examined. Charts were from the Ontario Ministry of Health and LongTerm Care Critical Care Information Systemic database, and were interrogated by two reviewers. Results: In patients whose EOL status changed following RRT EOL discussion, there were fewer intensive care unit (ICU) transfers (8.4% versus 17%; P<0.001), decreased ICU length of stay (5.8 days versus 20 days; P=0.08), increased palliative care consultations (34% versus 5.3%; P<0.001) and an increased proportion who died within 24 h of consultation (25% versus 8.3%; P<0.001). More patients experienced a change in EOL status following the introduction of an EOL PPO, from 20% (before) to 31% (after) (P<0.05). ConClusions: A change in EOL status following RRT-led EOL discussion was associated with reduced ICU transfers and enhanced access to palliative care services. Further study is required to identify and deconstruct barriers impairing timely and appropriate EOL discussions. Effect of RRTs on EOL care Can Respir J Vol 21 No 5 September/October 2014 303 (Hamilton, Ontario), a 458-bed tertiary care centre and regional centre of excellence specializing in cardiac and vascular care, neuroscience, trauma and burn treatment, stroke and rehabilitation. The RRT at the authors' site has been a Ministry of Health and Long-Term Care of Ontario-funded team since 2006 and includes an ICU physician, critical care nurses and registered respiratory therapists. Critical care residents or fellows may support the team on some occasions. Any health care provider with concerns regarding patients' airway, breathing or circulation can activate the team. The nurses and respiratory therapists on the RRT also have several medical directives that allows them to initiate resuscitative therapy before a licensed physician arrives at the bedside. They have also received additional training in EOL discussions. The POST was implemented in January 2010 as a hospital-wide policy to improve EOL care. Institutional policy dictated that the POST form was to be completed for all hospitalized patients with a predicted life expectancy <1 year. Before its implementation, there was a one-month period of distributed education on using the POST form. The POST form was examined because it coincided with the study period and was a confounder that may have effected RRT EOL discussions. ethics The present study was approved by Hamilton Health Sciences Research Ethics Board (approval number was 11-463-C). The need for informed consent was waived. data collection The chart review was composed of all patients seen by the RRT team between January 1, 2009 and December 31, 2010. RRT-based EOL discussions were tracked. Data were gathered from the Ontario Ministry of Health and Long-Term Care Critical Care Information Systemic database. Charts were divided into code status discussion initiated, code status discussion revisited, code status previously established and code status discussion not appropriate at the time or for this patient. These distinctions were determined by the RRT's registered nurse or respiratory therapist, who completed the team call record at the time of RRT consultation. Charts coded as 'discussion initiated' and 'discussion revisited' were considered to be positive for EOL discussion. Two reviewers reviewed the charts independently. If the RRT had an EOL discussion, the patient's medical record was reviewed for patient demographics, admitting service, code status at time of consultation, completion of POST form, a change in EOL status following consultation, ICU transfer following consultation, total ICU length of stay (LOS) following transfer, if death occurred within 24 h following consultation and whether palliative care was involved in EOL care. data analysis The analysis focused on RRT EOL discussion with critically ill ward patients. To determine the effect of the RRT on EOL care, patients with and without a change in EOL status following RRT EOL discussion were compared. To determine the effect of the POST form on RRT EOL discussions, the outcomes before the introduction of the POST (January 1, 2009 to December 31 2009) and following the introduction of the POST (January 1, 2010 to Decemebr 31, 2010) were compared. Discrete variables were described as proportions and compared using χ 2 tests. Continuous variables were reported as mean ± SD and compared using unpaired t tests; P<0.05 was considered to be statistically significant. Results Patient population Between January 1, 2009 and December 31, 2010, the RRT saw 5320 patients. Of 5320 patients, 1254 (24%) were seen as a new RRT consultation while 3155 (59%) were seen in ICU discharge follow-up. The method in which RRT was involved was not documented for 911 patients (17%). Three hundred nineteen patients (6%) had their code status discussion initiated or revisited by the RRT; 3081 (58%) had a previously established code status. A code status discussion was deemed not appropriate for 1920 patients (36%) effect of RRt eol discussion on eol care Of the patients who RRT initiated or revisited code status, 276 (89%) were for full resuscitation at the time of consultation. The EOL status was changed in 83 (27%) patients, all of whom were for full resuscitation at the time of consultation. In patients with a change in EOL status, there were fewer ICU transfers (8% versus 16%; P<0.01), more palliative services arranged (34% versus 5%; P<0.01) and more patients who passed away within 24 h of RRT consultation (25% versus 8%; P<0.01). There was a trend toward decreased ICU LOS (six days versus 20 days; P=0.08) ( effect of Post form on eol care There were minimal differences when comparing outcomes before and following POST implementation. There were similar proportions of patients who were for full resuscitation at time of consultation (89% before versus 85% after; P=0.72). There was a significant increase in the proportion of patients who had a change in code status following implementation of the POST form (20% before versus 31% after; P<0.05). However, there was no difference in proportion transferred to the ICU (13% before versus 15% after; P=0.55), average ICU LOS (12 days before versus 14 days after; P=0.38), nor was there a difference in proportion with palliative care involved (14% before versus 12% after; P=0.55). There was a trend toward increased proportion of patients who died within 24 h of RRT consultation (8.6% before versus 16% after; P=0.08) ( disCussion We found that RRTs influenced EOL care through EOL discussions. In patients who experienced a change in EOL status following RRT EOL discussion, there were fewer ICU transfers, increased palliative services and more patients who died within 24 h. Furthermore, the POST form may be a tool that is associated with more EOL discussions, although it did not impact other EOL outcomes in our critical care setting. RRT involvement in EOL care is an evolving concept. Vasquez et al The extent of RRT involvement in EOL care is not yet clear. Downar et al (9,10) found that RRT involvement was not associated with improved access to palliative services, spiritual care and comfort medications. This outcome may be attributed to the study population. Downar et al (10) compared EOL care for patients who had died with versus without RRT consult. Patients referred to the RRT may have had a reversible condition amenable to restorative therapy as opposed to palliation. Conversely, patients who were not referred may have had irreversible conditions more suited to palliative care. This was suggested by the significantly increased proportion of patients with irreversible poor prognostic factors, palliative care consultations and shorter time to withdrawal of life support (10). In contrast, we studied patients who the RRT selected for an EOL discussion at the time of RRT consultation. As such, our study suggests that the RRT was able to identify and treat patients who would benefit from palliative care in the critical care setting. Although our study showed that RRTs could successfully initiate EOL care in critical care scenarios, this may not by the optimal time to discuss goals of care and resuscitation status. RRT involvement in EOL care suggests that there was room to enhance predeterioration EOL care. Previous studies have shown that clinical deterioration is not a sudden process and that the majority of cases present with antecedent clues such as hypotension or hypoxia (19). Responding to these clinical perturbations is only part of the care process. These fluctuations in clinical status should act as stop points for all health care providers to reassess the goals of care and resuscitation status with the patients and families. However, EOL care is not well addressed in hospital. Heyland (20) found that 76% of elderly patients have considered EOL care and only 12% preferred life-prolonging care. However, only 30% of medical documentation accurately reflected the patients' wishes. Reasons for not documenting an EOL status could be influenced by the patient and family, the clinician or the institution. Family/patient factors included unrealistic patients and families, inability of patients to participate in discussions and lack of advance directives (21,22). Clinician factors included insufficient training, competing time demands and insufficient remuneration (21-24). Institutional factors included suboptimal space for family meetings and lack of palliative care services Enhancing EOL quality will require multitiered interventions enacted through institutions, clinicians and patient/families. One intervention our institute implemented to support EOL discussions is the POST form. Previous literature suggested that similar forms may be used in a hospice or long-term care setting to effectively ensure adherence to patient wishes in an EOL setting (11-13). However, benefit of the POST form requires further study in critical care settings (15). Curtis et al Enhanced in-hospital EOL care is unlikely to arise from policy changes alone. There is room to improve clinician involvement in EOL care. O'Mahony et al (26) reported successful integration of a palliative care team into an ICU. They found that there was increased opioid use, formalized advanced directives and utilization of hospices, in addition to decreased investigations and nonbeneficial life-prolonging therapies. Furthermore, it is important to consider patient and family factors in a comprehensive plan for improving in-hospital EOL care. Heyland One systematic difference that may have influenced the results of our study was patient illness severity. The change in EOL status following RRT involvement may have been driven by illness severity as opposed to RRT EOL discussions. Due to data limitations, we were unable to determine whether there were any systematic differences in illness severity between patients who had a change in EOL status and those who did not. Even if this was the case, increased illness severity in patients with high unlikelihood of benefiting from resuscitative measures should drive EOL discussions and subsequent EOL care. The present study would then suggest that RRTs had the ability to identify deteriorating patients who benefited from palliation rather than resuscitation. More work is required to determine how accurately RRTs prognosticate patients. Furthermore, although we selected quantifiable and patientimportant outcomes to review, the scope of our analysis was limited by data restrictions inherent in a retrospective study. We found that 26% of patients who had an EOL discussion with the RRT had a subsequent change in EOL status; we do not know whether this number was appropriate. Seventy-four percent of patients who the RRT believed warranted an EOL discussion did not have a subsequent change in EOL status. EOL discussions could have resulted in more than a change in EOL status. Other outcomes that may have been affected include dyspnea management, avoiding unnecessary and invasive therapies, treatment of pain, ascertaining patient and family values, and providing support suMMARy We found that a change in EOL status following RRT-led EOL discussions was associated with reduced ICU transfers and enhanced access to palliative services. Our study suggested that there is a need to enhance predeterioration EOL planning. Moreover, there is a need to develop institutional support for EOL care, clinician training on EOL care and enhanced access to palliative care services. Future areas of study are to identify patients who will benefit from EOL discussion and to identify the barriers to engaging these patients in EOL discussion. ACknoWledgeMents: BT contributed to research design, dat
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