Challenges in understanding, measuring, and managing technical debt

Abstract. Technical debt as a concept is vast and somewhat abstract area. The most basic definition of it is that it is analogous to a bank loan, which must be paid back so you don’t get stated bankrupt. Number of activities required to manage the debt are numerous, as 15 different sources of possible debt are identified. Technical debt management activities, possible sources, and outcomes that unpaid debt might bring are documented in this paper’s background section. Results section contains challenges that technical debt management processes are encountering in understanding, measuring, and managing the debt. Even with existing empirical research on technical debt management, research and industry are having hard time in trying to find the right tools and areas to measure to gain meaningful information on numerous types of technical debt. Without the right metrics, the monitoring tools are not able to provide useful information to aid in communication and decision-making. Currently, the tools focus mainly on code smells (code debt) and are not able to measure the most important aspects of the debt, design, and architectural debt. This research suggests future research topics to improve existing knowledge on certain areas such as the previously mentioned ability to meaningfully measure different kinds of debts

CMM-2013 -Computer Methods in Mechanics

Abstract In Eurocode 3: Design of steel structures -Part 1-2: General rules -Structural fire design, the temperatures in the steel section are assumed uniform and the thermal properties are assumed constant. This leads to conservative and possibly uneconomic designs. In particular, steel sections embedded in or in direct contact with concrete are not considered appropriately -only the reduction of the exposed area is taken into account. In addition, the shadow effect is rarely considered in structures with both concrete and asteel elements such as composite floors. It has been mainly used for stand-alone columns with I-cross section. In this paper, the temperature distributions in a steel beam with or without considering the shadow effect are calculated using the program TASEF. The resulting temperatures are then used to determine the fire duration under loading using a finite difference based computer program COMPSEF for the mechanical response. The differences in failure times reflect the savings that can be made using such 'advanced calculation models' permitted in Eurocode 3, when compared with the prescriptive methods included in the code

Mechanical Forces in the Skin : Roles in Tissue Architecture, Stability, and Function

Tissue shape emerges from the collective mechanical properties and behavior of individual cells and the ways by which they integrate into the surrounding tissue. Tissue architecture and its dynamic changes subsequently feed back to guide cell behavior. The skin is a dynamic, self-renewing barrier that is subjected to large-scale extrinsic mechanical forces throughout its lifetime. The ability to withstand this constant mechanical stress without compromising its integrity as a barrier requires compartment-specific structural specialization and the capability to sense and adapt to mechanical cues. This review discusses the unique mechanical properties of the skin and the importance of signals that arise from mechanical communication between cells and their environment.Peer reviewe

Hydrostatic pressure prevents chondrocyte differentiation through heterochromatin remodeling

Articular cartilage protects and lubricates joints for smooth motion and transmission of loads. Owing to its high water content, chondrocytes within the cartilage are exposed to high levels of hydrostatic pressure, which has been shown to promote chondrocyte identity through unknown mechanisms. Here, we investigate the effects of hydrostatic pressure on chondrocyte state and behavior, and discover that application of hydrostatic pressure promotes chondrocyte quiescence and prevents maturation towards the hyperlrophic state. Mechanistically, hydrostatic pressure reduces the amount of trimethylated H3K9 (K3K9me3)-marked constitutive heterochromatin and concomitantly increases H3K27me3-marked facultative heterochromatin. Reduced levels of H3K9me3 attenuates expression of pre-hypertrophic genes, replication and transcription, thereby reducing replicative stress. Conversely, promoting replicative stress by inhibition of topoisomerase II decreases Sox9 expression, suggesting that it enhances chondrocyte maturation. Our results reveal how hydrostatic pressure triggers chromatin remodeling to impact cell fate and function. This article has an associated First Person interview with the first author of the paper.Peer reviewe

N1-acetylspermidine is a determinant of hair follicle stem cell fate

Stem cell differentiation is accompanied by increased mRNA translation. The rate of protein biosynthesis is influenced by the polyamines putrescine, spermidine and spermine, which are essential for cell growth and stem cell maintenance. However, the role of polyamines as endogenous effectors of stem cell fate and whether they act through translational control remains obscure. Here, we investigate the function of polyamines in stem cell fate decisions using hair follicle stem cell (HFSC) organoids. Compared to progenitor cells, HFSCs showed lower translation rates, correlating with reduced polyamine levels. Surprisingly, overall polyamine depletion decreased translation but did not affect cell fate. In contrast, specific depletion of natural polyamines mediated by spermidine/spermine N1-acetyltransferase (SSAT; also known as SAT1) activation did not reduce translation but enhanced stemness. These results suggest a translation-independent role of polyamines in cell fate regulation. Indeed, we identified N1-acetylspermidine as a determinant of cell fate that acted through increasing self-renewal, and observed elevated N1-acetylspermidine levels upon depilation-mediated HFSC proliferation and differentiation in vivo. Overall, this study delineates the diverse routes of polyamine metabolism-mediated regulation of stem cell fate decisions. This article has an associated First Person interview with the first author of the paper.Peer reviewe

Pain, psychological distress and health-related quality of life at baseline and 3 months after radical prostatectomy

BACKGROUND: Inadequate management of postoperative pain is common, and postoperative pain is a risk factor for prolonged pain. In addition to medical and technical factors, psychological factors may also influence the experience of postoperative pain. METHODS: Pain was measured postoperatively at 24, 48, and 72 hr in hospital and after 3 months at home in 140 patients undergoing radical prostatectomy (RP). Patients answered questionnaires about anxiety and depression (HAD scale) and health-related quality of life (SF-36) at baseline and 3 months after surgery. RESULTS: In the first 3 postoperative days, mild pain was reported by 45 patients (32%), moderate pain by 64 (45%), and severe pain by 31 (22%) on one or more days. High postoperative pain scores were correlated with length of hospital stay and with high pain scores at home. Forty patients (29%) reported moderate (n = 35) or severe (n = 5) pain after discharge from hospital. Patients who experienced anxiety and depression preoperatively had higher postoperative pain scores and remained anxious and depressed 3 months after surgery. The scores for the physical domains in the SF-36 were decreased, while the mental health scores were increased at 3 months. Anxiety and depression were negatively correlated with all domains of the SF-36. CONCLUSION: There is a need for nurses to be aware of the psychological status of RP patients and its impact upon patients' experience of postoperative pain and recovery. The ability to identify patients with psychological distress and to target interventions is an important goal for future research

Response of stone wool-insulated building barriers under severe heating exposures

This article presents the experimental results of stone wool-layered sandwich constructions, with either steel or gypsum claddings, tested under four different heating exposures: 7kW/m(2) incident radiant heat flux exposure, 60kW/m(2) incident radiant heat flux exposure, parametric time-temperature curve exposure and ISO 834 standard time-temperature exposure. The test apparatus used were a movable radiant panel system, a mid-scale furnace (1.5m(3)) and a large-scale furnace (15m(3)). The results show that reduced-scale tests are capable of reproducing the heat transferred through the construction at large scale provided there is limited mechanical degradation. The results indicate that the availability of oxygen is fundamental to the fire behaviour of the sandwich composites tested. Reactions occurring in stone wool micro-scale testing, such as oxidative combustion of the binder or crystallisation of the fibres, have a limited effect on the temperature increase when wool is protected from air entrainment