The Twisted String Vertex Algorithm Applied to the Z2Z_2-Twisted Scalar String Four Vertex

Recently an algorithm was found by means of which one can calculate terms at arbitrary oscillator level in the four-Ramond vertex obtained by sewing. Here we show that this algorithm is applicable also to the case of ${\bf Z}_2$-twisted scalars and derive the full propagator for scalars on the Riemann sphere with two branch cuts. The relation to similar results previously derived in the literature by other means is discussed briefly.Comment: 18 pages (LaTeX), G\"oteborg ITP 94-

An Algorithm for Computing Four-Ramond Vertices at Arbitrary Level

We perform the sewing of two (dual) Ramond reggeon vertices and derive an algorithm by means of which the so obtained four-Ramond reggeon vertex may be explicitly computed at arbitrary oscillator (mass) level. A closed form of the four-vertex is then deduced on the basis of a comparison to all terms obtained by sewing that contain only level zero and one oscillators. Results are presented for both complex fermions and for the previously studied case of real fermions.Comment: 31 pages, Latex, Goteborg ITP 92-5

Loops, Twists and String Vertices: The Sewing Approach to String Perturbation Theory

String theory provides the most promising candidate for a unified theory of all fundamental forces and a consistent quantum mechanical theory of gravity. String theory is, at present, defined through its perturbation expansion. There exists various methods for treating the string diagrams one of which is through the sewing of Reggeon vertices. We investigate the sewing procedure for both untwisted and twisted strings. Ordinary untwisted strings satisfy periodic boundary conditions whereas the twisted strings pick up non-zero phases when taken around the origin in complex z- plane. Apart from the Ramond sector of the superstring, twisted strings are also relevant in connection with string propagation on orbifolds and the construction of realistic string models. For untwisted strings, it is well understood how to perform the sewing and it is possible to derive completely general answers for string scattering amplitudes. In Papers I and IV, we show that the construction of loop vertices is simplified if we take the basic building blocks to be dual four-Reggeon vertices instead of the usual Sciuto- Della Selva-Saito three vertices. For twisted strings, such as the Ramond string, the situation is much more complicated. For vertices involving four external twisted strings, answers have previously only been derived through sewing for external ground states. In Paper II, we extend these results and give an algorithm by means of which the four vertex can be calculated for arbitrary external states. This is used to find the closed form of the vertex for scattering of four Ramond fermions. In Paper V, we use this algorithm, and the dual vertex for twisted scalars constructed in Paper I, to investigate the four-Reggeon vertex for Z2- twisted scalar fields. In Paper III, we generalize the sewing procedure to fields with higher twists; in this case Z3-twisted fermions

Loops, Twists and String Vertices: The Sewing Approach to String Perturbation Theory

String theory provides the most promising candidate for a unified theory of all fundamental forces and a consistent quantum mechanical theory of gravity. String theory is, at present, defined through its perturbation expansion. There exists various methods for treating the string diagrams one of which is through the sewing of Reggeon vertices. We investigate the sewing procedure for both untwisted and twisted strings. Ordinary untwisted strings satisfy periodic boundary conditions whereas the twisted strings pick up non-zero phases when taken around the origin in complex z- plane. Apart from the Ramond sector of the superstring, twisted strings are also relevant in connection with string propagation on orbifolds and the construction of realistic string models. For untwisted strings, it is well understood how to perform the sewing and it is possible to derive completely general answers for string scattering amplitudes. In Papers I and IV, we show that the construction of loop vertices is simplified if we take the basic building blocks to be dual four-Reggeon vertices instead of the usual Sciuto- Della Selva-Saito three vertices. For twisted strings, such as the Ramond string, the situation is much more complicated. For vertices involving four external twisted strings, answers have previously only been derived through sewing for external ground states. In Paper II, we extend these results and give an algorithm by means of which the four vertex can be calculated for arbitrary external states. This is used to find the closed form of the vertex for scattering of four Ramond fermions. In Paper V, we use this algorithm, and the dual vertex for twisted scalars constructed in Paper I, to investigate the four-Reggeon vertex for Z2- twisted scalar fields. In Paper III, we generalize the sewing procedure to fields with higher twists; in this case Z3-twisted fermions

Distansarbetets påverkan för byggnadskonstruktörer : En kvalitativ fallstudie om hur konstruktörers effektivitet & kvalitet påverkats av distansarbete

Byggbranschen i Sverige har till följd av Covid-19-pandemin tvingats till en påskyndad digitalisering vilket har bidragit till ökad användning av digitala verktyg och distansarbete. Tidigare forskning inom ämnet indikerar på både positiva och negativa konsekvenser av distansarbete och återkommande faktorer är arbetsmiljön, kommunikationen, kunskapsdelningen och de tekniska förutsättningarna. Studien undersöker hur konstruktörer på ett medelstort byggföretag i Sverige påverkas inom aspekterna effektivitet och kvalitét vid övergången till distansarbete samt om det är en lämplig arbetsmetod att använda permanent i framtiden. För att besvara studiens frågeställningar har författarna valt att använda intervjuer för att undersöka upplevelsen av distansarbete och en datainsamling för att kontrollera effektiviteten och kvaliteten. Intervjumetoden i studien är en semistrukturerad intervju med fem utvalda konstruktörer på företaget som medverkat i studien. Insamlingen av rådata till studien hämtades från företagets interna tidsrapporteringssystem, kvalitetsdokument från företagets underentreprenörer samt en kompletterande enkätundersökning.   Respondenterna i studien upplevde att konstruktörernas effektivitet minskats vilket inte överensstämmer med studiens statistiska data. Resultatet visar att effektiviteten ökat och kvaliteten på konstruktörernas dokument är likvärdig även efter övergången till distansarbete. Författarnas bedömning efter genomförd studie, är att distansarbete är en bra arbetsmetod att tillämpa om det är ett valbart komplement för konstruktörerna. En permanent övergång till distansarbete kan innebära att konstruktörerna upplever en minskad tillhörighet till företaget, mindre gemenskap med övriga medarbetare, en försvårad kommunikation och försämrad kunskapsdelning vilket på sikt kan påverka effektiviteten och kvaliteten på konstruktörernas dokument.As a result of the Covid-19 pandemic, the construction industry in Sweden has been forced to accelerate the digitalization process, which has contributed to an increased use of digital tools and teleworking. Previous research in the subject indicates both positive and negative consequences of teleworking and recurring factors are the work environment, communication, knowledge sharing and technology. The study examines how designers at a medium-sized construction company in Sweden are affected within the aspects of efficiency and quality in the transition to telework and whether it is a suitable working method to use permanently in the future or not. To answer the questions in this study, the authors have chosen to use an interview method to examine the experience of telework and a data collection to check the effectiveness and quality. The interview method in the study is a semi-structured interview with five selected designers at the company that participated in this study. The collection of data for the study was given from the company's internal time reporting system, quality documents from the company’s subcontractors and a supplementary survey. The respondents in the study felt that the designers’ efficiency was reduced, which do not correspond with statistical data in the study. The results show that efficiency has increased and the quality of the designers' documents is equivalent in the transition to telework. The authors' assessment after the implementation of the study is that teleworking is a good working method to apply if it is an optional complement for the designers. A permanent transition to teleworking can mean that the designers experience a reduced affiliation to the company, less fellowship with other employees, a more difficult communication and impaired knowledge sharing, which in the long run can affect the efficiency and quality of the designers' documents

Proteomic Analysis and Discovery Using Affinity Proteomics and Mass Spectrometry*

Antibody-based microarrays are a rapidly evolving affinity-proteomic methodology that recently has shown great promise in clinical applications. The resolution of these proteomic analyses is, however, directly related to the number of data-points, i.e. antibodies, included on the array. Currently, this is a key bottleneck because of limited availability of numerous highly characterized antibodies. Here, we present a conceptually new method, denoted global proteome survey, opening up the possibility to probe any proteome in a species-independent manner while still using a limited set of antibodies. We use context-independent-motif-specific antibodies directed against short amino acid motifs, where each motif is present in up to a few hundred different proteins. First, the digested proteome is exposed to these antibodies, whereby motif-containing peptides are enriched, which then are detected and identified by mass spectrometry. In this study, we profiled extracts from human colon tissue, yeast cells lysate, and mouse liver tissue to demonstrate proof-of-concept