bluuebunny/crossref_metadata_2025 huggingface dataset:
Two mechanisms for dust gap opening in protoplanetary discs
Authors: Dipierro Giovanni , Laibe Guillaume , Price Daniel J. , Lodato Giuseppe
Published: March 2016

We identify two distinct physical mechanisms for dust gap opening by embedded planets in protoplanetary discs based on the symmetry of the drag-induced motion around the planet: (I) a mechanism where low-mass planets, that do not disturb the gas, open gaps in dust by tidal torques assisted by drag in the inner disc, but resisted by drag in the outer disc; and (II) the usual, drag-assisted, mechanism where higher mass planets create pressure maxima in the gas disc, which the drag torque then acts to evacuate further in the dust. The first mechanism produces gaps in dust but not gas, while the second produces partial or total gas gaps which are deeper in the dust phase. Dust gaps do not necessarily indicate gas gaps.
The Johns Hopkins Hunterian Laboratory Philosophy: Mentoring Students in a Scientific Neurosurgical Research Laboratory
Authors: Tyler Betty M. , Liu Ann , Sankey Eric W. , Mangraviti Antonella , Barone Michael A. , Brem Henry
Published: March 2016

After over 50 years of scientific contribution under the leadership of Harvey Cushing and later Walter Dandy, the Johns Hopkins Hunterian Laboratory entered a period of dormancy between the 1960s and early 1980s. In 1984, Henry Brem reinstituted the Hunterian Neurosurgical Laboratory, with a new focus on localized delivery of therapies for brain tumors, leading to several discoveries such as new antiangiogenic agents and Gliadel chemotherapy wafers for the treatment of malignant gliomas. Since that time, it has been the training ground for 310 trainees who have dedicated their time to scientific exploration in the lab, resulting in numerous discoveries in the area of neurosurgical research. The Hunterian Neurosurgical Laboratory has been a unique example of successful mentoring in a translational research environment. The laboratory’s philosophy emphasizes mentorship, independence, self-directed learning, creativity, and people-centered collaboration, while maintaining productivity with a focus on improving clinical outcomes. This focus has been served by the diverse backgrounds of its trainees, both in regard to educational status as well as culturally. Through this philosophy and strong legacy of scientific contribution, the Hunterian Laboratory has maintained a positive and productive research environment that supports highly motivated students and trainees. In this article, the authors discuss the laboratory’s training philosophy, linked to the principles of adult learning (andragogy), as well as the successes and the limitations of including a wide educational range of students in a neurosurgical translational laboratory and the phenomenon of combining clinical expertise with rigorous scientific training.
Burnout and Alcohol Abuse/Dependence Among U.S. Medical Students
Authors: Jackson Eric R. , Shanafelt Tait D. , Hasan Omar , Satele Daniel V. , Dyrbye Liselotte N.
Published: March 2016

Purpose

To explore the relationship between alcohol abuse/dependence with burnout and other forms of distress among a national cohort of medical students.

Method

In 2012, the authors completed a national survey of medical students from the American Medical Association’s Physician Masterfile containing validated items assessing alcohol abuse/dependence, burnout, depression, suicidality, quality of life (QOL), and fatigue. Descriptive and comparative statistical analyses were computed, including chi-square and multivariate logistic regression, to determine relationships between variables.

Results

Of the 12,500 students, 4,402 (35.2%) responded. Of these, 1,411 (32.4%) met diagnostic criteria for alcohol abuse/dependence. Students who were burned out (P = .01), depressed (P = .01), or reported low mental (P =.03) or emotional (P = .016) QOL were more likely to have alcohol abuse/dependence. Emotional exhaustion and depersonalization domains of burnout were strongly associated with alcohol abuse/dependence. On multivariate analysis, burnout (OR 1.20; 95% CI 1.05–1.37; P < .01), having $50,000 to $100,000 (OR 1.21 versus < $50,000; CI 1.02–1.44; P < .05) or > $100,000 (OR 1.27 versus < $50,000; CI 1.08–1.48; P < .01) of educational debt, being unmarried (OR 1.89; CI 1.57–2.27; P < .001), and being younger (for every five years, OR 1.15; CI 1.02–1.28; P = .01) were independently associated with increased risk for alcohol abuse/dependence.

Conclusions

Burnout was strongly related to alcohol abuse/dependence among sampled medical students and increased educational debt predicted a higher risk. A multifaceted approach addressing burnout, medical education costs, and alcohol use is needed.
Adductor Canal Block Provides Noninferior Analgesia and Superior Quadriceps Strength Compared with Femoral Nerve Block in Anterior Cruciate Ligament Reconstruction
Authors: Abdallah Faraj W. , Whelan Daniel B. , Chan Vincent W. , Prasad Govindarajulu A. , Endersby Ryan V. , Theodoropolous John , Oldfield Stephanie , Oh Justin , Brull Richard
Published: March 2016

AbstractAbstract

In a randomized trial of 100 subjects undergoing anterior cruciate ligament, analgesia from adductor canal block was not inferior to that of femoral nerve block, but quadriceps muscle strength was superior.

Background

By targeting the distal branches of the femoral nerve in the mid-thigh, the adductor canal block (ACB) can preserve quadriceps muscle strength while providing analgesia similar to a conventional femoral nerve block (FNB) for inpatients undergoing major knee surgery. In this randomized, double-blind, noninferiority trial, the authors hypothesized that ACB provides postoperative analgesia that is at least as good as FNB while preserving quadriceps strength after outpatient anterior cruciate ligament reconstruction.

Methods

A total of 100 patients were randomized to receive ACB or FNB with 20 ml ropivacaine 0.5% (with epinephrine). The authors sequentially tested the joint hypothesis that ACB is noninferior to FNB for cumulative oral morphine equivalent consumption and area under the curve for pain scores during the first 24 h postoperatively and also superior to FNB for postblock quadriceps maximal voluntary isometric contraction.

Results

The authors analyzed 52 and 48 patients who received ACB and FNB, respectively. Compared with preset noninferiority margins, the ACB–FNB difference (95% CI) in morphine consumption and area under the curve for pain scores were −4.8 mg (−12.3 to 2.7) (P = 0.03) and −71 mm h (−148 to 6) (P < 0.00001), respectively, indicating noninferiority of ACB for both outcomes. The maximal voluntary isometric contraction for ACB and FNB at 45 min were 26.6 pound-force (24.7–28.6) and 10.6 pound-force (8.3–13.0) (P < 0.00001), respectively, indicating superiority of ACB.

Conclusion

Compared with FNB, the study findings suggest that ACB preserves quadriceps strength and provides noninferior postoperative analgesia for outpatients undergoing anterior cruciate ligament reconstruction.
Infusion System Architecture Impacts the Ability of Intensive Care Nurses to Maintain Hemodynamic Stability in a Living Swine Simulator
Authors: Pezone Matthew J. , Peterfreund Robert A. , Maslov Mikhail Y. , Govindaswamy Radhika R. , Lovich Mark A.
Published: March 2016

AbstractAbstract

We investigated the ability of skilled intensive care unit registered nurses to overcome pharmacologic delays caused by large infusion system common volumes in a swine model. The data suggest that smaller common volume leads to better hemodynamic control.

Background

The authors have previously shown that drug infusion systems with large common volumes exhibit long delays in reaching steady-state drug delivery and pharmacodynamic effects compared with smaller common-volume systems. The authors hypothesized that such delays can impede the pharmacologic restoration of hemodynamic stability.

Methods

The authors created a living swine simulator of hemodynamic instability in which occlusion balloons in the aorta and inferior vena cava (IVC) were used to manipulate blood pressure. Experienced intensive care unit nurses blinded to the use of small or large common-volume infusion systems were instructed to maintain mean arterial blood pressure between 70 and 90 mmHg using only sodium nitroprusside and norepinephrine infusions. Four conditions (IVC or aortic occlusions and small or large common volume) were tested 12 times in eight animals.

Results

After aortic occlusion, the time to restore mean arterial pressure to range (t
1: 2.4 ± 1.4 vs. 5.0 ± 2.3 min, P = 0.003, average ± SD), time-out-of-range (t
OR: 6.2 ± 3.5 vs. 9.5 ± 3.4 min, P = 0.028), and area-out-of-range (pressure–time integral: 84 ± 47 vs. 170 ± 100 mmHg·min, P = 0.018) were all lower with smaller common volumes. After IVC occlusion, t
1 (3.7 ± 2.2 vs. 7.1 ± 2.6 min, P = 0.002), t
OR (6.3 ± 3.5 vs. 11 ± 3.0 min, P = 0.007), and area-out-of-range (110 ± 93 vs. 270 ± 140 mmHg·min, P = 0.003) were all lower with smaller common volumes. Common-volume size did not impact the total amount infused of either drug.

Conclusions

Nurses did not respond as effectively to hemodynamic instability when drugs flowed through large common-volume infusion systems. These findings suggest that drug infusion system common volume may have clinical impact, should be minimized to the greatest extent possible, and warrants clinical investigations.
Iron Parameters Determine the Prognosis of Critically Ill Patients*
Authors: Tacke Frank , Nuraldeen Renwar , Koch Alexander , Strathmann Klaus , Hutschenreuter Gabriele , Trautwein Christian , Strnad Pavel
Published: March 2016

Objective:

Because iron is both an essential and toxic micronutrient influencing the development of microbial infections, we evaluated the usefulness of iron parameters as outcome predictors in ICU patients.

Design:

Prospective clinical single-center non-interventional study.

Setting:

General internal medicine ICU; German University hospital.

Patients:

One hundred and twelve septic and 43 nonseptic ICU patients, 156 healthy blood donors.

Measurements and Main Results:

Serum iron parameters at admission were correlated with short and long term mortality in ICU subjects. Both hepcidin and ferritin concentrations were significantly elevated in ICU patients compared with blood donors and were the highest in septic patients. On the contrary, serum iron and transferrin levels were decreased in ICU subjects with lowest values among septic patients. Hepcidin values correlated with ferritin levels, and serum iron correlated strongly with transferrin saturation. A moderate correlation of hepcidin, ferritin, and transferrin with inflammatory parameters was noted. Both short- and long-term survivors displayed higher ferritin/transferrin levels and lower transferrin saturation. In Kaplan-Meier analyses, low iron levels (cutoff 10.5 μmol/mL), low transferrin saturation (cutoff 55%), and high serum transferrin concentrations (cutoff 1.6 g/L) were associated with short- and long-term survival. In the subgroup of septic ICU subjects, low iron levels and transferrin saturation went along with a nonlethal outcome.

Conclusions:

Our findings demonstrate that parameters of iron metabolism, particularly transferrin saturation, that reflect serum iron availability, are strong outcome predictors in ICU patients. These data suggest that a failure of iron homeostasis with increased iron availability in serum occurs in lethally ill ICU patients and should trigger prospective clinical trials evaluating the usefulness of iron-chelating therapy in critical illness and sepsis.
Adjuvant Corticosteroid Treatment in Adults With Influenza A (H7N9) Viral Pneumonia*
Authors: Cao Bin , Gao Hainv , Zhou Boping , Deng Xilong , Hu Chengping , Deng Chaosheng , Lu Hongzhou , Li Yuping , Gan Jianhe , Liu Jingyuan , Li Hui , Zhang Yao , Yang Yida , Fang Qiang , Shen Yinzhong , Gu Qin , Zhou Xianmei , Zhao Wei , Pu Zenghui , Chen Ling , Sun Baoxia , Liu Xi , Hamilton Carol Dukes , Li Lanjuan
Published: March 2016

Objective:

To determine the impact of adjuvant corticosteroids administered to patients hospitalized with influenza A (H7N9) viral pneumonia.

Design:

The effects of adjuvant corticosteroids on mortality were assessed using multivariate Cox regression and a propensity score-matched case-control study. Nosocomial infections and viral shedding were also compared.

Setting:

Hospitals with influenza A (H7N9) viral pneumonia patient admission in 84 cities and 16 provinces of Mainland China.

Patients:

Adolescent and Adult patients aged >14 yr with severe laboratory-confirmed influenza A (H7N9) virus infections were screened from April 2013 to March 2015.

Interventions:

None.

Measurements and Main Results:

The study population comprised 288 cases who were hospitalized with influenza A (H7N9) viral pneumonia. The median age of the study population was 58 years, 69.8% of the cohort comprised male patients, and 51.4% had at least one type of underlying diseases. The in-hospital mortality was 31.9%. Two hundred and four patients (70.8%) received adjuvant corticosteroids; among them, 193 had hypoxemia and lung infiltrates, 11 had chronic obstructive pulmonary disease, and 11 had pneumonia only. Corticosteroids were initiated within 7 days (interquartile range, 5.0–9.4 d) of the onset of illness and the maximum dose administered was equivalent to 80-mg methylprednisolone (interquartile range, 40–120 mg). The patients were treated with corticosteroids for a median duration of 7 days (interquartile range, 4.0–11.3 d). Cox regression analysis showed that compared with the patients who did not receive corticosteroid, those who received corticosteroid had a significantly higher 60-day mortality (adjusted hazards ratio, 1.98; 95% CI, 1.03–3.79; p = 0.04). Subgroup analysis showed that high-dose corticosteroid therapy (> 150 mg/d methylprednisolone or equivalent) significantly increased both 30-day and 60-day mortality, whereas no significant impact was observed for low-to-moderate doses of corticosteroids (25–150 mg/d methylprednisolone or equivalent). The propensity score–matched case-control analysis showed that the median viral shedding time was much longer in the group that received high-dose corticosteroids (15 d), compared with patients who did not receive corticosteroids (13 d; p = 0.039).

Conclusions:

High-dose corticosteroids were associated with increased mortality and longer viral shedding in patients with influenza A (H7N9) viral pneumonia.
Comparison of Population Pharmacokinetics Based on Steady-State Assumption Versus Electronically Monitored Adherence to Lopinavir, Atazanavir, Efavirenz, and Etravirine: A Retrospective Study
Authors: Fuchs Aline , Rotzinger Aurélie , Cavassini Matthias , Bugnon Olivier , Buclin Thierry , Schneider Marie Paule , Csajka Chantal
Published: March 2016

Background:

Population pharmacokinetic (PopPK) analyses often rely on steady state and full adherence to prescribed dosage regimen assumptions from data gathered during therapeutic drug monitoring (TDM). Nonadherence is common in chronic diseases such as HIV. This study evaluates the impact of adherence measurement by electronic monitoring on PopPK parameter estimation and individual concentration profile predictions, and also the influence of adherence issues on the clinical interpretation of a concentration measurement.

Methods:

Published PopPK models for lopinavir, atazanavir, efavirenz, and etravirine were applied to estimate PK parameters and individual concentrations in 140 HIV patients taking part in a medication adherence program using 2 dosing data sets. The first set included the last dose reported by the patient with steady-state and full adherence assumptions; the second set used detailed electronic dosing history. PopPK parameter estimates and individual predictions were compared between the 2 dosing entries.

Results:

Clearance estimates and likewise predicted concentrations did not markedly differ between the 2 dosing histories. However, certain patterns of nonadherence such as sparse missed doses or consecutive missed doses lead to suboptimal drug exposure. The interpretation based on self-reported information would have concluded on a wrongly appropriate individual exposure.

Conclusions:

PopPK analysis assuming steady state with full adherence produced similar results to those based on detailed electronic dosing history reconciled with patients' allegations. Self-reported last dose intake appeared reliable for concentration predictions and therapeutic drug monitoring interpretation for most patients followed at the medication adherence program. Yet, clinicians should be aware that concentration predictions based on self-reported last dose intake might be overestimated in case of undetected patterns of nonadherence, increasing the risk of forthcoming therapeutic failure.
CENTRAL SEROUS CHORIORETINOPATHY IN POSTMENOPAUSAL WOMEN RECEIVING EXOGENOUS TESTOSTERONE
Authors: Conway Mandi D. , Noble Jason A. , Peyman Gholam A.
Published: March 2016

Purpose:

Central serous chorioretinopathy (CSR) is a serous detachment of the neurosensory retina commonly associated with male sex, Type-A personality and corticosteroid use. Exogenous administration of androgens and development of CSR in men has been reported. Only one case of CSR in a postmenopausal woman receiving exogenous androgen therapy has been reported. The authors describe three cases of chronic CSR in postmenopausal women receiving exogenous testosterone therapy.

Methods:

Diagnosis was based on characteristic clinical, fluorescein angiographic, and optical coherence tomography findings. The three women were being treated with exogenous testosterone and progesterone therapy for symptoms of menopause and libido loss.

Results:

Average age at presentation was 54.7 years (53–56 years), average duration of exogenous androgen use was 61 months (36–87 months), with average 19.7-month follow-up. Resolution of symptoms seemed correlated with cessation of androgen use despite treatment with oscillatory photodynamic therapy and intravitreal pharmacotherapy with antivascular endothelial growth factor agents.

Conclusion:

Exogenous testosterone is increasingly prescribed for menopausal symptoms and libido loss. Treatment with oscillatory photodynamic therapy, supplemental bevacizumab intravitreal pharmacotherapy, and cessation of exogenous androgen therapy was successful in three cases of chronic, therapy-resistant CSR. Ophthalmologists should inquire about androgen usage in patients who present with CSR, especially in the setting of therapy resistance.
Predictors of fecal transplant failure
Authors: Meighani Alireza , Hart Benjamin R. , Mittal Chetan , Miller Nichole , John Ajin , Ramesh Mayur
Published: March 2016

Background

Clostridium difficile infection (CDI) is a significant healthcare burden, with increased morbidity and mortality. Traditional treatment regimens using antibiotics for recurrent CDI are significantly less successful compared with 80–90% with fecal microbiota transplantation (FMT). There is a paucity of data on failure rates and mortality after FMT in CDI. This study aims to identify the rates of failure, relapse, and mortality associated with FMT as well as the risk factors for FMT failure.

Methods

A large retrospective cohort study was carried out including all patients who underwent FMT from December 2012 through May 2014. Patient factors (demographics, comorbidities, immune-suppression, transplant history, antibiotics used, hospitalization, and surgeries), disease factors (number of episodes of CDI, treatments, and severity), and transplant factors (route and number of FMT) were examined. Failure of treatment was defined as no resolution of diarrhea in patients who had been treated with one or more fecal microbiota transplantation within 90 days of FMT.

Results

A total of 201 patients (age 66.6±18.3 years, 62.2% women) were included. The overall failure rate was 12.4%. Patients with failed fecal transplant had increased number of FMTs compared with those who responded (mean 1.92±0.997 vs. 1.29±0.615; P=0.004). No colectomies or death related to CDI were found in our patient population. Significant predictors of failure were female sex (P=0.016), previous hospitalization (P=0.006), and surgery before FMT (P=0.005). The overall mortality rate was 9.0% and failure of FMT was associated with an increased risk of death (odds ratio=5.833, confidence interval 2.01–16.925; P<0.05).

Conclusion

FMT is a suitable alterative to antibiotic use for recurrent CDIs, with a high success rate. The results indicate that hospital-acquired CDI may be a predictor of failure of FMT.
In Vivo Anti-Inflammatory and Analgesic Effects of Aqueous Extract of Cistus ladanifer L. From Morocco
Authors: El Hamsas El Youbi Amal , El Mansouri Latifa , Boukhira Smahane , Daoudi Abdeljlil , Bousta Dalila
Published: March 2016

This study is designed to evaluate the analgesic and anti-inflammatory activities of aqueous extract (AE) of Cistus ladanifer L. leaves in experimental animal models. The central analgesic activity of C. ladanifer AE is studied using hot plate method in rats, and the acute anti-Inflammatory activity of C. ladanifer is investigated by rats paw edema induced by subplantar injection of 0.5% carrageenan into the right hind paw. Rats are pretreated with AE of C. ladanifer at different doses (150, 175, and 200 mg/kg, i.p.). The tramadol and indomethacin are used as reference drugs for analgesic and anti-inflammatory studies, respectively. Our results show that the AE of C. ladanifer exhibited anti-inflammatory and analgesic effects dose dependent. In anti-inflammatory activity, the AE of C. ladanifer at all doses reduced significantly the edema paw inflammation after carrageenan injection. Furthermore at 200 mg/kg, the effect of AE is highly important than that of other doses. In addition, the same AE demonstrates significant analgesic effect in thermal-induced pain model. So, this activity is proved by significant reduction of pain score after administration of AE at all doses. The nociception protection effects in this case are, respectively, 70.3%, 74.55%, and 93.33% after administration of AE of C. ladanifer at doses 150, 175, and 200 mg/kg b.w. The results of our findings suggest that AE of C. ladanifer has potential analgesic and anti-inflammatory activities with evidence of possible involvement of peripheral and central effects in its actions.
General Anesthesia in a Patient With Urticaria Pigmentosa Referred for Electroconvulsive Therapy
Authors: Aloysi Amy S. , Ahle Gabriella M. , Geduldig Emma , Kellner Charles H. , Bryson Ethan O.
Published: March 2016

Urticaria pigmentosa is a rare disorder characterized by an abnormal systemic proliferation of mast cells. In this condition, various triggers can induce either cutaneous histamine release, resulting in rash, or generalized histamine release, resulting in symptomatic hypotension, syncope, or in its severest form, an anaphylactoid reaction resistant to most resuscitative measures. Many anesthetic agents and adjuncts are known potential triggers, and patients who require surgery or procedures under anesthesia must be managed carefully. In this review, we describe the safe use of general anesthesia for electroconvulsive therapy in a patient with urticaria pigmentosa and discuss the association between psychiatric disorders and mastocytoses.
Assessing the Effects of Repetitive Transcranial Magnetic Stimulation on Cognition in Major Depressive Disorder Using Computerized Cognitive Testing
Authors: Galletly Cherrie , Gill Shane , Rigby Ashlee , Carnell Benjamin Luke , Clarke Patrick
Published: March 2016

Objectives

A range of different treatment approaches are available for depression; however, there is an ongoing concern about the cognitive impairment associated with many treatments. This study investigated the effect of treatment with repetitive transcranial magnetic stimulation (rTMS) on cognition in patients with major depressive disorder. Cognition before and after treatment was assessed using a computerized cognitive testing battery, which provided comprehensive assessment across a range of cognitive domains. This was a naturalistic study involving patients attending an outpatient clinical rTMS service.

Methods

A total of 63 patients with treatment-resistant depression completed the IntegNeuro cognitive test battery, a well-validated comprehensive computerized assessment tool before and after receiving 18 or 20 treatments of sequential bilateral rTMS. Change in the various cognitive domains was assessed, and analyses were undertaken to determine whether any change in cognition was associated with a change in rating of depression severity.

Results

There was a significant decrease in Hamilton Depression Rating Scale scores from baseline to posttreatment. There was no decline in performance on any of the cognitive tests. There were significant improvements in maze completion time and the number of errors in the maze task. However, these were accounted for by improvement in mood when change in depressive symptoms was included as a covariate.

Conclusions

This open-label study provides further support for the efficacy and safety of rTMS as a treatment option for people with major depressive disorder in a naturalistic clinical setting. Using a comprehensive, robust computerized battery of cognitive tests, the current study indicated that there was no significant cognitive impairment associated with rTMS and that any improvements in cognitive functioning were associated with a reduction in depressive symptoms.
Lineage tracing of the bivalve shell field with special interest in the descendants of the 2d blastomere
Authors: Mohri Masakuni , Hashimoto Naoki , Wada Hiroshi
Published: March 2016

By evolving bilaterally separated shell plates, bivalves acquired a unique body plan in which their soft tissues are completely protected by hard shell plates. In this unique body plan, mobility between the separated shell plates is provided by novel structures such as a ligament and adductor muscles. As a first step towards understanding how the bivalve body plan was established, we investigated the development of the separated shell plates and ligament. Over 100 years ago, it was hypothesized that the development of separated shell plates is tightly linked with the unique cell cleavage (division) pattern of bivalves during development, wherein each bilateral daughter cell of the 2d descendant 2d
1121
develops into one of the bilateral shell fields. In this study, we tested this hypothesis by tracing the cell lineages of the Japanese purple mussel
Septifer virgatus
. Although the shell fields were found to be exclusively derived from the bilateral descendant cells of 2d: 2d
11211
and 2d
11212
, the descendants of these cells were not restricted to shell fields alone, nor were they confined to the left or right side of the shell field based on their lineage. Our study demonstrated that ligament cells are also derived from 2d
11211
and 2d
11212
, indicating that the ligament cells emerged as a subpopulation of shell field cells. This also suggests that the establishment of the novel developmental system for the ligament cells was critical for the evolution of the unique body plan of bivalves.
Salinized rivers: degraded systems or new habitats for salt-tolerant faunas?
Authors: Kefford Ben J. , Buchwalter David , Cañedo-Argüelles Miguel , Davis Jenny , Duncan Richard P. , Hoffmann Ary , Thompson Ross
Published: March 2016

Anthropogenic salinization of rivers is an emerging issue of global concern, with significant adverse effects on biodiversity and ecosystem functioning. Impacts of freshwater salinization on biota are strongly mediated by evolutionary history, as this is a major factor determining species physiological salinity tolerance. Freshwater insects dominate most flowing waters, and the common lotic insect orders Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies) are particularly salt-sensitive. Tolerances of existing taxa, rapid adaption, colonization by novel taxa (from naturally saline environments) and interactions between species will be key drivers of assemblages in saline lotic systems. Here we outline a conceptual framework predicting how communities may change in salinizing rivers. We envision that a relatively small number of taxa will be saline-tolerant and able to colonize salinized rivers (e.g. most naturally saline habitats are lentic; thus potential colonizers would need to adapt to lotic environments), leading to depauperate communities in these environments.
Phosphorylation of the amino-terminus of the AGC kinase Gad8 prevents its interaction with TORC2
Authors: Du Wei , Forte Gabriella M. , Smith Duncan , Petersen Janni
Published: March 2016

Cell proliferation, metabolism, migration and survival are coordinated through the tight control of two target of rapamycin (TOR) kinase complexes: TORC1 and TORC2. Here, we show that a novel phosphorylation of fission yeast Gad8 (AGC kinase) on the evolutionarily conserved threonine 6 (Thr6) prevents the physical association between Gad8 and TORC2. Accordingly, this block to protein interactions by Gad8 Thr6 phosphorylation decreases TORC2-controlled activation of Gad8. Likewise, phosphorylation of Gad8 Thr6, possibly by PKC, prevents the association of Gad8 with TORC2 thereby increasing TORC2 activity, because it reduces Gad8-mediated feedback inhibition of TORC2. Consistently, the introduction of a Gad8 T6D mutant, that mimics phosphorylation, increased TORC2 activity. Increased PKCPck2expression prevented Gad8–TORC2 binding and so reduced the TORC2-mediated phosphorylation of Gad8 serine 546 that activates Gad8. Interestingly, independent of the Ser546 phosphorylation status, Gad8 Thr6 phosphorylation is important for remodelling the actin cytoskeleton and survival upon potassium ion and heat stresses. In contrast, Ser546 phosphorylation is required for the control of G1 arrest, mating, cell length at division and vascular size. Finally, these findings reveal a novel mode of TORC2 activation that is essential for cell survival following stress.
Deformation heterogeneity and texture in surface severe plastic deformation of copper
Authors: Basu Saurabh , Wang Zhiyu , Saldana Christopher
Published: March 2016

Comprehensive understanding of thermomechanical response and microstructure evolution during surface severe plastic deformation (S
2
PD) is important towards establishing controllable processing frameworks. In this study, the evolution of crystallographic textures during directional surface mechanical attrition treatment on copper was studied and modelled using the visco-plastic self-consistent framework.
In situ
high-speed imaging and digital image correlation of surface deformation in circular indentation were employed to elucidate mechanics occurring in a unit process deformation and to calibrate texture model parameters. Material response during directional surface mechanical attrition was simulated using a finite-element model coupled with the calibrated texture model. The crystallographic textures developed during S
2
PD were observed to be similar to those resultant from uniaxial compression. The implications of these results towards facilitating a processing-based framework to predict deformation mechanics and resulting crystallographic texture in S
2
PD configurations are briefly discussed.
Twofold orthogonal weavings on cuboids
Authors: Kovács Flórián
Published: March 2016

Some closed polyhedral surfaces can be completely covered by two-way, twofold (rectangular) weaving of strands of constant width. In this paper, a construction for producing all possible geometries for such weavable cuboids is proposed: a theorem on spherical octahedra is proven first that all further theory is based on. The construction method of weavable cuboids itself relies on successive truncations of an initial tetrahedron and is also extended for cases of degenerate (unbounded) polyhedra. Arguments are mainly based on the plane geometry of the development of the respective polyhedra, in connection with some of three-dimensional projective properties of the same.
Ocean acidification affects competition for space: projections of community structure using cellular automata
Authors: McCoy Sophie J. , Allesina Stefano , Pfister Catherine A.
Published: March 2016

Historical ecological datasets from a coastal marine community of crustose coralline algae (CCA) enabled the documentation of ecological changes in this community over 30 years in the Northeast Pacific. Data on competitive interactions obtained from field surveys showed concordance between the 1980s and 2013, yet also revealed a reduction in how strongly species interact. Here, we extend these empirical findings with a cellular automaton model to forecast ecological dynamics. Our model suggests the emergence of a new dominant competitor in a global change scenario, with a reduced role of herbivory pressure, or trophic control, in regulating competition among CCA. Ocean acidification, due to its energetic demands, may now instead play this role in mediating competitive interactions and thereby promote species diversity within this guild.
Reproductive competition triggers mass eviction in cooperative banded mongooses
Authors: Thompson Faye J. , Marshall Harry H. , Sanderson Jennifer L. , Vitikainen Emma I. K. , Nichols Hazel J. , Gilchrist Jason S. , Young Andrew J. , Hodge Sarah J. , Cant Michael A.
Published: March 2016

In many vertebrate societies, forced eviction of group members is an important determinant of population structure, but little is known about what triggers eviction. Three main explanations are: (i) the reproductive competition hypothesis, (ii) the coercion of cooperation hypothesis, and (iii) the adaptive forced dispersal hypothesis. The last hypothesis proposes that dominant individuals use eviction as an adaptive strategy to propagate copies of their alleles through a highly structured population. We tested these hypotheses as explanations for eviction in cooperatively breeding banded mongooses (
Mungos mungo
), using a 16-year dataset on life history, behaviour and relatedness. In this species, groups of females, or mixed-sex groups, are periodically evicted
en masse
. Our evidence suggests that reproductive competition is the main ultimate trigger for eviction for both sexes. We find little evidence that mass eviction is used to coerce helping, or as a mechanism to force dispersal of relatives into the population. Eviction of females changes the landscape of reproductive competition for remaining males, which may explain why males are evicted alongside females. Our results show that the consequences of resolving within-group conflict resonate through groups and populations to affect population structure, with important implications for social evolution.
A cost for high levels of sperm competition in rodents: increased sperm DNA fragmentation
Authors: delBarco-Trillo Javier , García-Álvarez Olga , Soler Ana Josefa , Tourmente Maximiliano , Garde José Julián , Roldan Eduardo R. S.
Published: March 2016

Sperm competition, a prevalent evolutionary process in which the spermatozoa of two or more males compete for the fertilization of the same ovum, leads to morphological and physiological adaptations, including increases in energetic metabolism that may serve to propel sperm faster but that may have negative effects on DNA integrity. Sperm DNA damage is associated with reduced rates of fertilization, embryo and fetal loss, offspring mortality, and mutations leading to genetic disease. We tested whether high levels of sperm competition affect sperm DNA integrity. We evaluated sperm DNA integrity in 18 species of rodents that differ in their levels of sperm competition using the sperm chromatin structure assay. DNA integrity was assessed upon sperm collection, in response to incubation under capacitating or non-capacitating conditions, and after exposure to physical and chemical stressors. Sperm DNA was very resistant to physical and chemical stressors, whereas incubation in non-capacitating and capacitating conditions resulted in only a small increase in sperm DNA damage. Importantly, levels of sperm competition were positively associated with sperm DNA fragmentation across rodent species. This is the first evidence showing that high levels of sperm competition lead to an important cost in the form of increased sperm DNA damage.
Diminished foraging performance of a mutant zebrafish with reduced population of ultraviolet cones
Authors: Novales Flamarique Iñigo
Published: March 2016

Ultraviolet (UV) cones are photoreceptors that sense light in the range 300–450 nm and are found in the retinas of non-mammalian vertebrates and small mammals. Despite their widespread presence across taxa, the functions that these cones exert in the lives of animals remain largely unknown. In this study, I used the zebrafishlor(lots of rods) mutant, characterized by a diminished UV cone population compared to that of wild-type zebrafish, to test whether its foraging performance differed from that of the wild-type (control). The mean location distance and angle (variables that are reliable indicators of foraging performance) at which control fish detected zooplankton prey were, on average, 24 and 90% greater than corresponding measures forlorfish. Such inferior foraging performance of the mutant could be explained by reduced contrast perception of the prey, resulting from the diminished population of UV cones and associated sensitivity. Thus, UV cones enhance the foraging performance of zebrafish, a crucial ecological function that may explain why small zooplanktivorous fishes retain UV cones throughout their lives.
A missense mutation inTUBD1is associated with high juvenile mortality in Braunvieh and Fleckvieh cattle
Authors: Schwarzenbacher Hermann , Burgstaller Johann , Seefried Franz R. , Wurmser Christine , Hilbe Monika , Jung Simone , Fuerst Christian , Dinhopl Nora , Weissenböeck Herbert , Fuerst-Waltl Birgit , Dolezal Marlies , Winkler Reinhard , Grueter Oskar , Bleul Ulrich , Wittek Thomas , Fries Ruedi , Pausch Hubert
Published: March 2016

Background

Haplotypes with reduced or missing homozygosity may harbor deleterious alleles that compromise juvenile survival. A scan for homozygous haplotype deficiency revealed a short segment on bovine chromosome 19 (Braunvieh haplotype 2, BH2) that was associated with high juvenile mortality in Braunvieh cattle. However, the molecular genetic underpinnings and the pathophysiology of BH2 remain to be elucidated.

Results

The frequency of BH2 was 6.5 % in 8,446 Braunvieh animals from the national bovine genome databases. Both perinatal and juvenile mortality of BH2 homozygous calves were higher than the average in Braunvieh cattle resulting in a depletion of BH2 homozygous adult animals (P=9.3x10−12). The analysis of whole-genome sequence data from 54 Braunvieh animals uncovered a missense mutation inTUBD1(rs383232842, p.H210R) that was compatible with recessive inheritance of BH2. The availability of sequence data of 236 animals from diverse bovine populations revealed that the missense mutation also segregated at a low frequency (1.7 %) in the Fleckvieh breed. A validation study in 37,314 Fleckvieh animals confirmed high juvenile mortality of homozygous calves (P=2.2x10−15). Our findings show that the putative disease allele is located on an ancestral haplotype that segregates in Braunvieh and Fleckvieh cattle. To unravel the pathophysiology of BH2, six homozygous animals were examined at the animal clinic. Clinical and pathological findings revealed that homozygous calves suffered from chronic airway disease possibly resulting from defective cilia in the respiratory tract.

Conclusions

A missense mutation inTUBD1is associated with high perinatal and juvenile mortality in Braunvieh and Fleckvieh cattle. The mutation is located on a common haplotype likely originating from an ancient ancestor of Braunvieh and Fleckvieh cattle. Our findings demonstrate for the first time that deleterious alleles may segregate across closed cattle breeds without recent admixture. Homozygous calves suffer from chronic airway disease resulting in poor growth performance and high juvenile mortality. The respiratory manifestations resemble key features of diseases resulting from impaired function of airway cilia.
Glycolytic enzymes localize to synapses under energy stress to support synaptic function
Authors: Jang SoRi , Nelson Jessica C. , Bend Eric G. , Rodríguez-Laureano Lucelenie , Tueros Felipe G. , Cartagenova Luis , Underwood Katherine , Jorgensen Erik M. , Colón-Ramos Daniel A.
Published: March 2016

Changes in neuronal activity create local and transient changes in energy demands at synapses. Here we discover a metabolic compartment that formsin vivonear synapses to meet local energy demands and support synaptic function inCaenorhabditis elegansneurons. Under conditions of energy stress, glycolytic enzymes redistribute from a diffuse localization in the cytoplasm to a punctate localization adjacent to synapses. Glycolytic enzymes colocalize, suggesting thead hocformation of a glycolysis compartment, or a ‘glycolytic metabolon’, that can maintain local levels of ATP. Local formation of the glycolytic metabolon is dependent on presynaptic scaffolding proteins, and disruption of the glycolytic metabolon blocks the synaptic vesicle cycle, impairs synaptic recovery, and affects locomotion. Our studies indicate that energy demands in neurons are met locally through the assembly of a glycolytic metabolon to sustain synaptic function and behavior.
Measuring epistasis in fitness landscapes: the correlation of fitness effects of mutations
Authors: Ferretti Luca , Schmiegelt Benjamin , Weinreich Daniel , Yamauchi Atsushi , Kobayashi Yutaka , Tajima Fumio , Achaz Guillaume
Published: March 2016

Genotypic fitness landscapes are constructed by assessing the fitness of all possible combinations of a given number of mutations. In the last years, several experimental fitness landscapes have been completely resolved. As fitness landscapes are high-dimensional, simple measures of their structure are used as statistics in empirical applications. Epistasis is one of the most relevant features of fitness landscapes. Here we propose a new natural measure of the amount of epistasis based on the correlation of fitness effects of mutations. This measure has a natural interpretation, captures well the interaction between mutations and can be obtained analytically for most landscape models. We discuss how this measure is related to previous measures of epistasis (number of peaks, roughness/slope, fraction of sign epistasis, Fourier-Walsh spectrum) and how it can be easily extended to landscapes with missing data or with fitness ranks only. Furthermore, the dependence of the correlation of fitness effects on mutational distance contains interesting information about the patterns of epistasis. This dependence can be used to uncover the amount and nature of epistatic interactions in a landscape or to discriminate between different landscape models.
Decomposing the site frequency spectrum: the impact of tree topology on neutrality tests
Authors: Ferretti Luca , Ledda Alice , Wiehe Thomas , Achaz Guillaume , Ramos-Onsins Sebastian E.
Published: March 2016

We investigate the dependence of the site frequency spectrum (SFS) on the topological structure of genealogical trees. We show that basic population genetic statistics – for instance estimators ofθor neutrality tests such as Tajima’sD– can be decomposed into components of waiting times between coalescent events and of tree topology. Our results clarify the relative impact of the two components on these statistics. We provide a rigorous interpretation of positive or negative values of an important class of neutrality tests in terms of the underlying tree shape. In particular, we show that values of Tajima’sDand Fay and Wu’sHdepend in a direct way on a peculiar measure of tree balance which is mostly determined by the root balance of the tree. We present a new test for selection in the same class as Fay and Wu’sHand discuss its interpretation and power. Finally, we determine the trees corresponding to extreme expected values of these neutrality tests and present formulae for these extreme values as a function of sample size and number of segregating sites.
Scholars’ research-related personal information collections
Authors: AL-Omar Mashael , Cox Andrew Martin
Published: March 2016

Purpose

– The purpose of the paper is to explore the character of scholars’ research-related personal information collections (PICs).

Design/methodology/approach

– The study was based on in-depth interviews and office tours of 17 scholars in Education and Health Sciences in a Kuwaiti Higher Education Institution.

Findings

– Scholars’ research-related PICs were added to throughout the research life-cycle. They were huge, diverse, hybrid and fragmented. Key factors shaping the collections were the pressure to do research, time pressure in general, quality of space available, technology opportunity, lack of support from central services, the need to collect Arabic material, self-presentation and self-management. Older scholars and non-Kuwaiti nationals experienced the pressures slightly differently.

Research limitations/implications

– The study was limited to scholars in two disciplines, in one institution in a developing world context. However the models produced are suggestive of factors involved in shaping of the research-related PICs of scholars in general.

Practical implications

– Failures in personal information management are a cause for concern in terms of data integrity and validity of research. Interventions could include training of early career researchers for a life time of collecting.

Originality/value

– This is the first study to examine the contents of scholars’ research-related PICs and to provide a model of factors shaping them.
Assessing disciplinary differences in faculty perceptions of information literacy competencies
Authors: Pinto Maria
Published: March 2016

Purpose

– Uncovering faculty members’ conceptions of Information Literacy (IL), as well as exploring their perceptions with regard to the importance given to a previously defined set of core IL competences grouped into four categories: searching, evaluation, processing and communication and dissemination. Ascertaining the possible differences among the five knowledge branches (arts and humanities, sciences, social and legal sciences, health sciences, and technical disciplines); and understanding the importance granted to a set of learning improvement initiatives by the faculty. The paper aims to discuss these issues.

Design/methodology/approach

– The survey was completed by a set of faculty members from the University of Granada (Spain). Data were collected using the IL-HUMASS survey. The research is based on subjective data, first approached from a descriptive point of view. Later, data correlation, analysis and non-parametric tests were used with the goal of finding significant differences of faculty perceptions among the relevant academic areas.

Findings

– Results suggest that more than half of the surveyed faculty have what the authors define as an Academic Concept of IL. The IL categories of communica\tion and dissemination and searching were graded in significance by the staff as being “very important,” while those of evaluation and processing were assigned a slightly lesser rating of “important.” Results suggest that IL awareness falls into two broad groups differentiated by subject discipline: those from health sciences, social and legal sciences and arts and humanities representing the first group, and sciences and technical disciplines the other.

Research limitations/implications

– This approach address the subjective status of faculty concepts in a single university, but also in all knowledge branches. Future research is needed.

Originality/value

– This is one of the few papers regarding faculty perceptions of IL.