A test of trophic cascade theory: fish and benthic assemblages across a predator density gradient on coral reefs

Removal of predators is often hypothesized to alter community structure through trophic cascades. However, despite recent advances in our understanding of trophic cascades, evidence is often circumstantial on coral reefs because fishing pressure frequently co-varies with other anthropogenic effects, such as fishing for herbivorous fishes and changes in water quality due to pollution. Australia’s outer Great Barrier Reef (GBR) has experienced fishing-induced declines of apex predators and mesopredators, but pollution and targeting of herbivorous fishes are minimal. Here, we quantify fish and benthic assemblages across a fishing-induced predator density gradient on the outer GBR, including apex predators and mesopredators to herbivores and benthic assemblages, to test for evidence of trophic cascades and alternative hypotheses to trophic cascade theory. Using structural equation models, we found no cascading effects from apex predators to lower trophic levels: a loss of apex predators did not lead to higher levels of mesopredators, and this did not suppress mobile herbivores and drive algal proliferation. Likewise, we found no effects of mesopredators on lower trophic levels: a decline of mesopredators was not associated with higher abundances of algae-farming damselfishes and algae-dominated reefs. These findings indicate that top-down forces on coral reefs are weak, at least on the outer GBR. We conclude that predator-mediated trophic cascades are probably the exception rather than the rule in complex ecosystems such as the outer GBR

Palliative care interventions in advanced dementia (Review)

Background Dementia is a chronic, progressive and ultimately fatal neurodegenerative disease. Advanced dementia is characterised by profound cognitive impairment, inability to communicate verbally and complete functional dependence. Usual care of people with advanced dementia is not underpinned universally by a palliative approach. Palliative care has focused traditionally on care of people with cancer but for more than a decade, there have been increased calls worldwide to extend palliative care services to include all people with life-limiting illnesses in need of specialist care, including people with dementia. Objectives To assess the effect of palliative care interventions in advanced dementia and to report on the range of outcome measures used. Search methods We searched ALOIS, the Cochrane Dementia and Cognitive Improvement Group's Specialized Register on 4 February 2016. ALOIS contains records of clinical trials identified from monthly searches of several major healthcare databases, trial registries and grey literature sources. We ran additional searches across MEDLINE (OvidSP), Embase (OvidSP), PsycINFO (OvidSP), CINAHL (EBSCOhost), LILACS (BIREME), Web of Science Core Collection (ISI Web of Science), ClinicalTrials.gov and the World Health Organization ICTRP trial portal to ensure that the searches were as comprehensive and as up-to-date as possible. Selection criteria We searched for randomised (RCT) and non-randomised controlled trials (nRCT), controlled before-and-after studies (CBA) and interrupted time series studies evaluating the impact of palliative care interventions for adults with dementia of any type, staged as advanced dementia by a recognised and validated tool. Participants could be people with advanced dementia, their family members, clinicians or paid care staff. We included clinical interventions and non-clinical interventions. Comparators were usual care or another palliative care intervention. We did not exclude studies on the basis of outcomes measured and recorded all outcomes measured in included studies. Data collection and analysis Two review authors independently assessed for inclusion all the potential studies we identified as a result of the search strategy. We resolved any disagreement through discussion or, when required, consulted with the rest of the review team. We independently extracted data and conducted assessment of methodological quality, using standard Cochrane methods. Main results We identified two studies of palliative care interventions for people with advanced dementia. We did not pool data due to the heterogeneity between the two trials in terms of the interventions and the settings. The two studies measured 31 different outcomes, yet they did not measure the same outcome. There are six ongoing studies that we expect to include in future versions of this review. Both studies were at high risk of bias, in part because blinding was not possible. This and small sample sizes meant that the overall certainty of all the evidence was very low. One individually randomised RCT (99 participants) evaluated the effect of a palliative care team for people with advanced dementia hospitalised for an acute illness. While this trial reported that a palliative care plan was more likely to be developed for participants in the intervention group (risk ratio (RR) 5.84, 95% confidence interval (CI) 1.37 to 25.02), the plan was only adopted for two participants, both in the intervention group, while in hospital. The palliative care plan was more likely to be available on discharge in the intervention group (RR 4.50, 95% CI 1.03 to 19.75). We found no evidence that the intervention affected mortality in hospital (RR 1.06, 95% CI 0.53 to 2.13), decisions to forgo cardiopulmonary resuscitation in hospital or the clinical care provided during hospital admission, but for the latter, event rates were low and the results were associated with a lot of uncertainty. One cluster RCT (256 participants, each enrolled with a family carer) evaluated the effect of a decision aid on end-of-life feeding options on surrogate decision-makers of nursing home residents with advanced dementia. Data for 90 participants (35% of the original study) met the definition of advanced dementia for this review and were re-analysed for the purposes of the review. In this subset, intervention surrogates had lower scores for decisional conflict measured on the Decisional Conflict Scale (mean difference -0.30, 95% CI -0.61 to 0.01, reduction of 0.3 to 0.4 units considered meaningful) and were more likely than participants in the control group to discuss feeding options with a clinician (RR 1.57, 95% CI 0.93 to 2.64), but imprecision meant that there was significant uncertainty about both results. Authors' conclusions Very little high quality work has been completed exploring palliative care interventions in advanced dementia. There were only two included studies in this review, with variation in the interventions and in the settings that made it impossible to conduct a meta-analysis of data for any outcome. Thus, we conclude that there is insufficient evidence to assess the effect of palliative care interventions in advanced dementia. The fact that there are six ongoing studies at the time of this review indicates an increased interest in this area by researchers, which is welcome and needed. Plain language summary Palliative care for people with advanced dementia Review question In this research, we wanted to see if palliative care helps people with advanced dementia or helps their family or carers. We also wanted to describe how researchers tried to measure the effect of palliative care. Background People with advanced dementia have serious memory problems and have problems making simple decisions. They are usually no longer able to communicate by talking. They need a lot of help from their carers. People with advanced dementia can live for a long time. It is very hard to say exactly how long a person with advanced dementia will live. Palliative care (or end-of-life care) is a particular way of caring for people who have diseases that cannot be cured. The main aims of palliative care are to reduce pain and to maintain the best possible quality of life as death approaches. Palliative care is used a lot with people with cancer but is not used much for people with advanced dementia. Study characteristics We examined the research published up to January 2016. We found only two suitable studies (189 people), both from the US. We also found six studies that were underway but the results were not yet published. Key results One study found that having a small team of doctors and nurses trained in palliative care made little difference to how people with advanced dementia were treated while in hospital. But, having this special team meant that more people had a palliative care plan when they were discharged from hospital. The other study measured if giving written information to relatives explaining the different methods that can be used to feed people with advanced dementia helped either the relatives or the person. This study found that giving relatives this information made it a little easier for relatives to make decisions about what methods would be used to feed the person with dementia. Certainty of evidence We only found two studies and the two palliative care methods in these studies were very different. We cannot be very certain about how accurate either of these results reported here are, partly because only a small number of people took part in the studies. So from these studies, it is hard to be sure whether palliative care makes a difference to people with advanced dementia. Final thoughts Little research has been done about people with advanced dementia, often because of ethical concerns. However, although it is hard to do research with people with dementia, more well-designed studies are required to work out how palliative care can be used best in this special population

Membrane proteins and proteomics: Love is possible, but so difficult

Despite decades of extensive research, the large-scale analysis of membrane proteins remains a difficult task. This is due to the fact that membrane proteins require a carefully balanced hydrophilic and lipophilic environment, which optimum varies with different proteins, while most protein chemistry methods work mainly, if not only, in water-based media. Taking this review [Santoni, Molloy and Rabilloud, Membrane proteins and proteomics: un amour impossible? Electrophoresis 2000, 21, 1054-1070] as a pivotal paper, the current paper analyzes how the field of membrane proteomics exacerbated the trend in proteomics, i.e. developing alternate methods to the historical two-dimensional electrophoresis, and thus putting more and more pressure on the mass spectrometry side. However, in the case of membrane proteins, the incentive in doing so is due to the poor solubility of membrane proteins. This review also shows that in some situations, where this solubility problem is less acute, two-dimensional electrophoresis remains a method of choice. Last but not least, this review also critically examines the alternate approaches that have been used for the proteomic analysis of membrane proteins

Detection of group A Streptococcus in tonsils from pediatric patients reveals high rate of asymptomatic streptococcal carriage

<p>Abstract</p> <p>Background</p> <p>Group A <it>Streptococcus </it>(GAS) causes acute tonsillopharyngitis in children, and approximately 20% of this population are chronic carriers of GAS. Antibacterial therapy has previously been shown to be insufficient at clearing GAS carriage. Bacterial biofilms are a surface-attached bacterial community that is encased in a matrix of extracellular polymeric substances. Biofilms have been shown to provide a protective niche against the immune response and antibiotic treatments, and are often associated with recurrent or chronic bacterial infections. The objective of this study was to test the hypothesis that GAS is present within tonsil tissue at the time of tonsillectomy.</p> <p>Methods</p> <p>Blinded immunofluorescent and histological methods were employed to evaluate palatine tonsils from children undergoing routine tonsillectomy for adenotonsillar hypertrophy or recurrent GAS tonsillopharyngitis.</p> <p>Results</p> <p>Immunofluorescence analysis using anti-GAS antibody was positive in 11/30 (37%) children who had tonsillectomy for adenotonsillar hypertrophy and in 10/30 (33%) children who had tonsillectomy for recurrent GAS pharyngitis. Fluorescent microscopy with anti-GAS and anti-cytokeratin 8 & 18 antibodies revealed GAS was localized to the tonsillar reticulated crypts. Scanning electron microscopy identified 3-dimensional communities of cocci similar in size and morphology to GAS. The characteristics of these communities are similar to GAS biofilms from <it>in vivo </it>animal models.</p> <p>Conclusion</p> <p>Our study revealed the presence of GAS within the tonsillar reticulated crypts of approximately one-third of children who underwent tonsillectomy for either adenotonsillar hypertrophy or recurrent GAS tonsillopharyngitis at the Wake Forest School of Medicine.</p> <p>Trial Registration</p> <p>The tissue collected was normally discarded tissue and no patient identifiers were collected. Thus, no subjects were formally enrolled.</p

Other-Sex Friendships in Late Adolescence: Risky Associations for Substance Use and Sexual Debut?

Adolescents’ friendships with other-sex peers serve important developmental functions, but they may also facilitate engagement in problem behavior. This study examines the unique contributions of other-sex friendships and friends’ behavior to alcohol use, smoking, and initiation of sexual intercourse among late adolescent girls and boys. A total of 320 adolescents (53% girls; 33% racial/ethnic minorities) provided sociometric nominations of friendships annually in grades 10–12. Friendship networks were derived using social network analysis in each grade. Adolescents and their friends also reported on their alcohol use, smoking, and sexual debut at each assessment. After controlling for demographics, previous problem behavior, and friends’ behavior, other-sex friendships in 10th grade were associated with initiation of smoking among girls over the following year, and other-sex friendships in 11th grade were linked with lower levels of subsequent alcohol use among boys. Additionally, friends’ smoking and sexual experience in 10th grade predicted the same behaviors for all adolescents over the following year. Other-sex friendships thus appear to serve as a risk context for adolescent girls’ smoking and a protective context for adolescent boys’ drinking. Promoting mixed-gender activities and friendships among older high school students may be helpful in reducing males’ alcohol use, but may need to incorporate additional components to prevent increases in females’ smoking

Search for New Physics in e mu X Data at D0 Using Sleuth: A Quasi-Model-Independent Search Strategy for New Physics

We present a quasi-model-independent search for the physics responsible for electroweak symmetry breaking. We define final states to be studied, and construct a rule that identifies a set of relevant variables for any particular final state. A new algorithm ("Sleuth") searches for regions of excess in those variables and quantifies the significance of any detected excess. After demonstrating the sensitivity of the method, we apply it to the semi-inclusive channel e mu X collected in 108 pb^-1 of ppbar collisions at sqrt(s) = 1.8 TeV at the D0 experiment during 1992-1996 at the Fermilab Tevatron. We find no evidence of new high p_T physics in this sample.Comment: 23 pages, 12 figures. Submitted to Physical Review

Probing BFKL Dynamics in the Dijet Cross Section at Large Rapidity Intervals in ppbar Collisions at sqrt{s}=1800 and 630 GeV

Inclusive dijet production at large pseudorapidity intervals (delta_eta) between the two jets has been suggested as a regime for observing BFKL dynamics. We have measured the dijet cross section for large delta_eta in ppbar collisions at sqrt{s}=1800 and 630 GeV using the DO detector. The partonic cross section increases strongly with the size of delta_eta. The observed growth is even stronger than expected on the basis of BFKL resummation in the leading logarithmic approximation. The growth of the partonic cross section can be accommodated with an effective BFKL intercept of a_{BFKL}(20GeV)=1.65+/-0.07.Comment: Published in Physical Review Letter

Ratio of the Isolated Photon Cross Sections at \sqrt{s} = 630 and 1800 GeV

The inclusive cross section for production of isolated photons has been measured in \pbarp collisions at $\sqrt{s} = 630$ GeV with the \D0 detector at the Fermilab Tevatron Collider. The photons span a transverse energy ($E_T$) range from 7-49 GeV and have pseudorapidity $|\eta| < 2.5$. This measurement is combined with to previous \D0 result at $\sqrt{s} = 1800$ GeV to form a ratio of the cross sections. Comparison of next-to-leading order QCD with the measured cross section at 630 GeV and ratio of cross sections show satisfactory agreement in most of the $E_T$ range.Comment: 7 pages. Published in Phys. Rev. Lett. 87, 251805, (2001