Working towards a gauge-invariant description of the Higgs model: from local composite operators to spectral density functions

We analyze different BRST invariant solutions for the introduction of a mass term in Yang-Mills (YM) theories. First, we analyze the non-local composite gauge-invariant field $A^h_{\mu}(x)$, which can be localized by the Stueckelberg-like field $\xi^a(x)$. This enables us to introduce a mass term in the $SU(N)$ YM model, a feature that has been indicated at a non-perturbative level by both analytical and numerical studies. We also consider the unitary Abelian Higgs model and investigate its spectral functions at one-loop order. This analysis allows to disentangle what is physical and what is not at the level of the elementary particle propagators, in conjunction with the Nielsen identities. We highlight the role of the tadpole graphs and the gauge choices to get sensible results. We also introduce an Abelian Curci-Ferrari action coupled to a scalar field to model a massive photon which, like the non-Abelian Curci-Ferarri model, is left invariant by a modified non-nilpotent BRST symmetry. Finally, the spectral properties of a set of local gauge-invariant composite operators are investigated in the $U(1)$ and $SU(2)$ Higgs model quantized in the 't Hooft $R_{\xi}$ gauge. These operators enable us to give a gauge-invariant description of the spectrum of the theory, thereby surpassing certain incommodities when using the standard elementary fields. The corresponding two-point correlation functions are evaluated at one-loop order and their spectral functions are obtained explicitly. It is shown that the spectral functions of the elementary fields suffer from a strong unphysical dependence from the gauge parameter $\xi$, and can even exhibit positivity violating behaviour. In contrast, the BRST invariant local operators exhibit a well defined positive spectral density.Comment: PhD thesis, september 202

Food Insecurity of Community College Students: Addressing Barriers to Improve Persistence and Retention

Food insecurity is a non-academic barrier that must be considered when determining factors affecting students’ persistence and retention in college. Through the literature reviewed, food insecurity of community college students and the impact and barriers they face is explored in detail. The proposed solution addresses the stigma and lack of awareness regarding food insecurity resources available on campuses. Targeted communication with all students at the start of each semester will allow individuals to assess their level of food security. Depending on the level of food security, a targeted communication plan will follow providing information on resources available. Faculty and staff will have opportunities to learn about food insecurity and how it impacts students; creating awareness and sharing opportunities for assistance. Additionally, this project proposes having a master of social work student conduct their required fieldwork on-campus, by helping students who need more individualized support for food insecurity. Lastly, this project offers an opportunity for students to learn how to cook nutritionally on a budget. Through each of these project components, the hope is students feel the institution has shown care by recognizing and providing resources to address non-academic barriers, ultimately leading to greater persistence and retention

Continuous-flow laboratory simulation of stream water quality changes downstream of an untreated wastewater discharge.

In regions of the world with poor provision of wastewater treatment, raw sewage is often discharged directly into surface waters. This paper describes an experimental evaluation of the fate of two organic chemicals under these conditions using an artificial channel cascade fed with a mix of settled sewage and river water at its upstream end and operated under continuous steady-state conditions. The experiments underpin an environmental risk assessment methodology based on the idea of an “impact zone” (IZ) – the zone downstream of wastewater emission in which water quality is severely impaired by high concentrations of unionised ammonia, nitrite and biochemical oxygen demand (BOD). Radiolabelled dodecane-6-benzene sulphonate (DOBS) and aniline hydrochloride were used as the model chemical and reference compound respectively. Rapid changes in 14C counts were observed with flow-time for both these materials. These changes were most likely to be due to complete mineralisation. A dissipation half-life of approximately 7.1 h was observed for the 14C label with DOBS. The end of the IZ was defined as the point at which the concentration of both unionised ammonia and nitrite fell below their respective predicted no-effect concentrations for salmonids. At these points in the cascade, approximately 83 and 90% of the initial concentration of 14C had been removed from the water column, respectively. A simple model of mineral nitrogen transformations based on Michaelis–Menten kinetics was fitted to observed concentrations of NH4, NO2 and NO3. The cascade is intended to provide a confirmatory methodology for assessing the ecological risks of chemicals under direct discharge co

Characterization of the Roco Protein Family in Dictyostelium discoideum

The Roco family consists of multidomain Ras-GTPases that include LRRK2, a protein mutated in familial Parkinson's disease. The genome of the cellular slime mold Dictyostelium discoideum encodes 11 Roco proteins. To study the functions of these proteins, we systematically knocked out the roco genes. Previously described functions for GbpC, Pats1, and QkgA (Roco1 to Roco3) were confirmed, while novel developmental defects were identified in roco4- and roco11-null cells. Cells lacking Roco11 form larger fruiting bodies than wild-type cells, while roco4-null cells show strong developmental defects during the transition from mound to fruiting body; prestalk cells produce reduced levels of cellulose, leading to unstable stalks that are unable to properly lift the spore head. Detailed phylogenetic analysis of four slime mold species reveals that QkgA and Roco11 evolved relatively late by duplication of an ancestor roco4 gene (later than ∼300 million years ago), contrary to the situation with other roco genes, which were already present before the split of the common ancestor of D. discoideum and Polysphondylium pallidum (before ∼600 million years ago). Together, our data show that the Dictyostelium Roco proteins serve a surprisingly diverse set of functions and highlight Roco4 as a key protein for proper stalk cell formation

What is or what ought to be? Hoe het idee van ‘vermogen tot lijden’ van Viktor Frankl toegepast kan worden in de behandeling voor mensen met een depressieve stoornis

Viktor Frankl onderscheidt zich door ‘lijden’ een bron van zin te noemen. Hij ontwikkelde de logotherapie waarin de wil-tot-betekenis centraal staat: het streven van de mens naar betekenis en zin in zijn of haar leven. Lijden kan volgens hem zingevend zijn door het vinden van betekenis in dit lijden. In dit onderzoek is gekeken naar de toepassing van dit ‘vermogen tot lijden’ in de behandeling van mensen met een depressie. Tien interviews zijn afgenomen, waarvan vijf met ervaringsdeskundigen en vijf met behandelaars in de GGZ. De zin in het lijden zelf blijkt beperkt aanwezig te zijn ten tijde van een klinische depressie. Wel kan er een sterk zingevende houding ten opzichte van het lijden worden aangenomen. Daarnaast kunnen werk, kennisvergaring en verbondenheid als zingevingsbron ervaren worden ten tijde van het lijden. Ook kan er achteraf, na enig herstel, zin aan het lijden zelf toegekend worden. Vermogen tot lijden lijkt nog steeds actueel te zijn in de huidige behandeling al heeft het een ander fundament. Zingeving wordt meer als een opportunistische aangelegenheid gezien. De wil-tot-betekenis heeft daarmee een eigentijdse invulling gekregen die minder omvat dan het oorspronkelijke idee. Concluderend wordt gesteld dat het vermogen tot lijden in de huidige behandeling van mensen met een depressieve stoornis hernieuwde aandacht zou moeten krijgen

The Roco protein family:a functional perspective

In this review, we discuss the evolutionary, biochemical, and functional data available for members of the Roco protein family. They are characterized by having a conserved supradomain that contains a Ras-like GTPase domain, called Roc, and a characteristic COR (C-terminal of Roc) domain. A kinase domain and diverse regulatory and protein protein interaction domains are also often found in Roco proteins. First detected in the slime mold Dictyostelium discoideum, they have a broad phylogenetic range, being present in both prokaryotes and eukaryotes. The functions of these proteins are diverse. The best understood are Dictyostelium Rocos, which are involved in cell division, chemotaxis, and development. However, this family has received extensive attention because mutations in one of the human Roco genes (LRRK2) cause familial Parkinson disease. Other human Rocos are involved in epilepsy and cancer. Biochemical data suggest that Roc domains are capable of activating kinase domains intramolecularly. Interestingly, some of the dominant, disease-causing mutations in both the GTPase and kinase domains of LRRK2 increase kinase activity. Thus, Roco proteins may act as stand-alone transduction units, performing roles that were thought so far to require multiple proteins, as occur in the Ras transduction pathway

ACTIVITIES AND SPACE USE FOR ENABLING LOCAL ECONOMY IN COASTAL LOW INCOME HOUSING

Many low income households are supported by Home Based Enterprises (HBE) for their income generation. However the settlements in coastal areas have physical problems related to the corrosive land and climate condition, as well as the possi-bilities of natural hazards such as flooding (ADB, 2003 : UNHABITAT 2003). The rapid growths of cities especially in developing countries (DCs) contribute to social problems, serious burdens for human health and the environment. In order to imp-rove the quality of human life in the coastal cities, some local government decided to remove some settlements to the inland area such as problems in some big coastal cities in Indonesia. In many cases, many resettlements of housing failed to meet community’s and user’s requirements. To reduce and avoid sustainability problems, it is necessary to have more insight and understanding of the used of space in coastal low income housing. This paper describes the use of communal spaces for daily activities which are indicating the lack of space available in coastal settlements in order to accomodate user’s needs