Cornering Colored Coannihilation

In thermal dark matter models, allowing the dark matter candidate to coannihilate with another particle can considerably loosen the relic density constraints on the dark matter mass. In particular, introducing a single strongly interacting coannihilation partner in a dark matter model can bring the upper bound on the dark sector energy scale from a few TeV up to about 10 TeV. While these energies are outside the LHC reach, a large part of the parameter space for such coannihilating models can be explored by future hadron colliders. In this context, it is essential to determine whether the current bounds on dark matter simplified models also hold in non-minimal scenarios. In this paper, we study extended models that include multiple coannihilation partners. We show that the relic density bounds on the dark matter mass in these scenarios are stronger than for the minimal models in most of the parameter space and that weakening these bounds requires sizable interactions between the different species of coannihilation partners. Furthermore, we discuss how these new interactions as well as the additional particles in the models can lead to stronger collider bounds, notably in jets plus missing transverse energy searches. This study serves as a vital ingredient towards the determination of the highest possible energy scale for thermal dark matter models.Comment: 47 pages, 12 figure

Simplified Phenomenology for Colored Dark Sectors

We perform a general study of the relic density and LHC constraints on simplified models where the dark matter coannihilates with a strongly interacting particle X. In these models, the dark matter depletion is driven by the self-annihilation of X to pairs of quarks and gluons through the strong interaction. The phenomenology of these scenarios therefore only depends on the dark matter mass and the mass splitting between dark matter and X as well as the quantum numbers of X. In this paper, we consider simplified models where X can be either a scalar, a fermion or a vector, as well as a color triplet, sextet or octet. We compute the dark matter relic density constraints taking into account Sommerfeld corrections and bound state formation. Furthermore, we examine the restrictions from thermal equilibrium, the lifetime of X and the current and future LHC bounds on X pair production. All constraints are comprehensively presented in the mass splitting versus dark matter mass plane. While the relic density constraints can lead to upper bounds on the dark matter mass ranging from 2 TeV to more than 10 TeV across our models, the prospective LHC bounds range from 800 to 1500 GeV. A full coverage of the strongly coannihilating dark matter parameter space would therefore require hadron colliders with significantly higher center of mass energies.Comment: 34 pages, 8 figures, matches JHEP versio

Hunting for Dark Matter Coannihilation by Mixing Dijet Resonances and Missing Transverse Energy

Simplified models of the dark matter (co)annihilation mechanism predict striking new collider signatures untested by current searches. These models, which were codified in the coannihilation codex, provide the basis for a dark matter (DM) discovery program at the Large Hadron Collider (LHC) driven by the measured DM relic density. In this work, we study an exemplary model featuring $s$-channel DM coannihilation through a scalar diquark mediator as a representative case study of scenarios with strongly interacting coannihilation partners. We discuss the full phenomenology of the model, ranging from low energy flavor constraints, vacuum stability requirements, and precision Higgs effects to direct detection and indirect detection prospects. Moreover, motivated by the relic density calculation, we find significant portions of parameter space are compatible with current collider constraints and can be probed by future searches, including a proposed analysis for the novel signature of a dijet resonance accompanied by missing transverse energy (MET). Our results show that the $13$ TeV LHC with $100~\mathrm{fb}^{-1}$ luminosity should be sensitive to mediators as heavy as 1 TeV and dark matter in the 400--500 GeV range. The combination of searches for single and paired dijet peaks, non-resonant jets + MET excesses, and our novel resonant dijet + MET signature have strong coverage of the motivated relic density region, reflecting the tight connections between particles determining the dark matter abundance and their experimental signatures at the LHC.Comment: 35 pages, 9 figure

Stress, Anxiety, and Weight Gain among University and College Students: A Systematic Review

Abstract Background Stress and anxiety levels are elevated among university and college students. Although high stress levels can lead to an increase in adiposity, it is not clear whether stress and anxiety experienced when in university or college have an influence on students\u27 weight. Objective The aim of this systemic review was to investigate whether stress and anxiety levels encountered during university and college enrollment were associated with higher adiposity or weight changes among students. Method A search strategy was used to identify peer-reviewed studies published between 1985 and March 2017 using the following databases: Medline using Ovid; PubMed, CINAHL using EBSCO, Embase using Ovid, PSYCHINFO, and Open Access Theses and Dissertation. Two reviewers independently assessed the title, abstract, and then the full article of the studies that met the inclusion criteria. Data were extracted and quality assessment was conducted for the included studies. Results Twenty-five observational studies were identified in this review (23 cross-sectional and two longitudinal); 11 found that there was no association between stress and body mass index or weight change. In addition, five studies did not find a significant association between anxiety and body mass index. A few studies revealed stress and anxiety might be associated with higher or lower weight status, thus there is a possibility that stress can increase or decrease weight, demonstrating that a bidirectional influence on body mass index may exist. Conclusions The current data in this review are inadequate to draw firm conclusions about the role of stress on weight change in university and college students. The inconsistency of results in the literature reviewed for this article suggest that a focus on longitudinal studies with adequate sample size would better evaluate the relationship between stress or anxiety and its influence on weight status or weight change among college and university students

Progression of Anterograde Trans-Synaptic Degeneration in the Human Retina Is Modulated by Axonal Convergence and Divergence.

In the visual pathway of patients with multiple sclerosis (MS), the inner nuclear layer (INL) of the retina is a tight barrier for retrograde trans-synaptic degeneration. In this observational, retrospective cross-sectional study, segmented macular spectral domain optical coherence tomography (OCT) volume scans were reviewed to investigate if this observation also holds true for anterograde trans-synaptic degeneration. Significant thinning was found in all retinal layers in patients with outer retinal diseases compared with the healthy controls, while there was no significant attenuation of the outer retina in patients with MS. In contrast to the tight barrier function observed with retrograde trans-synaptic degeneration, the INL appears to be more permissive for the propagation of anterograde trans-synaptic degeneration. We speculate that this may be due to the size of the area affected and be explained by convergence and divergence of axons within the retinal layers. These findings are likely relevant to future restorative stem cell treatment of the outer retinal layers, as time may matter

The Tn916/Tn1545 Family of Conjugative Transposon

The conjugative transposon Tn916 was first discovered in the late 1970s and is, together with the related conjugative transposon Tn1545, the paradigm of a large family of related conjugative transposons known as the Tn916/Tn1545 family, which are found in an extremely diverse range of bacteria. With the huge increase in bacterial genomic sequence data available, due to the widespread use of next generation sequencing, more putative conjugative transposons belonging to the Tn916/Tn1545 family are being reported. Many of these are capable of excision, integration and conjugation. Nearly all of the Tn916/Tn1545‑like elements discovered to date encode tetracycline resistance however, increasingly resistance to other antimicrobials is being found. Some of the members of the Tn916/Tn1545 family of elements are composite structures which contain smaller mobile genetic elements which are also capable of transposition. Tn916/Tn1545‑like elements themselves are also found within larger and more complex elements. This review will give an overview of the current knowledge of the Tn916/Tn1545 family of conjugative transposons highlighting recently characterized composite elements carrying additional and novel resistance genes

Growth and hydrolase profiles can be used as characteristics to distinguish Aspergillus niger and other black aspergilli

Wild type Aspergillus niger isolates from different biotopes from all over the world were compared to each other and to the type strains of other black Aspergillus species with respect to growth and extracellular enzyme profiles. The origin of the A. niger isolate did not result in differences in growth profile with respect to monomeric or polymeric carbon sources. Differences were observed in the growth rate of the A. niger isolates, but these were observed on all carbon sources and not specific for a particular carbon source. In contrast, carbon source specific differences were observed between the different species. Aspergillus brasiliensis is the only species able to grow on D-galactose, and A. aculeatus had significantly better growth on Locus Bean gum than the other species. Only small differences were found in the extracellular enzyme profile of the A. niger isolates during growth on wheat bran, while large differences were observed in the profiles of the different black aspergilli. In addition, differences were observed in temperature profiles between the black Aspergillus species, but not between the A. niger isolates, demonstrating no isolate-specific adaptations to the environment

The Influence of Oral Health Factors on the Quality of Life in Older People: A Systematic Review

Background and Objectives: The number of people aged 65 years or older is growing substantially. As a result of increased health burden and tooth retention, more oral health problems are expected in this age group. A poor oral health-related quality of life (OHQoL) can compromise a person’s psychological state, social relationships, personal beliefs, and physical health. The aim of this systematic review was to identify oral health factors associated with OHQoL in people aged 65 years or older and to give a comprehensive overview of the body of literature for each oral health factor separately. // Research Design and Methods: A comprehensive search was performed in five databases. The following terms were used as index terms or free-text words: “Oral Health,” “Quality of Life,” “Older People.” Two researchers independently assessed studies for eligibility based on predefined criteria. // Results: Of 3,702 references retrieved from the databases, 68 studies were eligible and included (9 randomized clinical trials, 6 cohort studies, and 53 cross-sectional studies). All results were reported descriptively. OHQoL in people aged 65 years or older is positively associated with higher number of teeth, higher number of occluding pairs, implant-retained overdentures, and the shortened dental arch concept and negatively associated with xerostomia, orofacial pain, and poor chewing ability. In the current literature, there is no consensus on the association between edentulism, caries, and periodontal conditions and OHQoL. // Discussion and Implications: Having a functional dentition (either natural or prosthetic) is important for a good OHQoL, whereas painful or functional complaints are associated with impaired OHQoL