1,660 research outputs found
Real-Time Ginzburg-Landau Theory for Bosons in Optical Lattices
Within the Schwinger-Keldysh formalism we derive a Ginzburg-Landau theory for
the Bose-Hubbard model which describes the real-time dynamics of the complex
order parameter field. Analyzing the excitations in the vicinity of the quantum
phase transitions it turns out that particle/hole dispersions in the Mott phase
map continuously onto corresponding amplitude/phase excitations in the
superfluid phase. Furthermore, in the superfluid phase we find a sound mode,
which is in accordance with recent Bragg spectroscopy measurements in the
Bogoliubov regime, as well as an additional gapped mode, which seems to have
been detected via lattice modulation
Excitation Spectra of Bosons in Optical Lattices from Schwinger-Keldysh Calculation
Within the Schwinger-Keldysh formalism we derive a Ginzburg-Landau theory for
the Bose-Hubbard model which describes the real-time dynamics of the complex
order parameter field. Analyzing the excitations in the vicinity of the quantum
phase transition it turns out that particle/hole dispersions in the Mott phase
map continuously onto corresponding amplitude/phase excitations in the
superfluid phase, which have been detected recently by Bragg spectroscopy
measurements
Preoperative Nutritional Conditioning of Crohn's Patients-Systematic Review of Current Evidence and Practice.
Crohn's disease is an incurable and frequently progressive entity with major impact on affected patients. Up to half of patients require surgery in the first 10 years after diagnosis and over 75% of operated patients require at least one further surgery within lifetime. In order to minimize surgical risk, modifiable risk factors such as nutritional status need to be optimized. This systematic review on preoperative nutritional support in adult Crohn's patients between 1997 and 2017 aimed to provide an overview on target populations, screening modalities, routes of administration, and expected benefits. Pertinent study characteristics (prospective vs. retrospective, sample size, control group, limitations) were defined a priori. Twenty-nine studies were retained, of which 14 original studies (9 retrospective, 4 prospective, and 1 randomized controlled trial) and 15 reviews. Study heterogeneity was high regarding nutritional regimens and outcome, and meta-analysis could not be performed. Most studies were conducted without matched control group and thus provide modest level of evidence. Consistently, malnutrition was found to be a major risk factor for postoperative complications, and both enteral and parenteral routes were efficient in decreasing postoperative morbidity. Current guidelines for nutrition in general surgery apply also to Crohn's patients. The route of administration should be chosen according to disease presentation and patients' condition. Further studies are needed to strengthen the evidence
Lower gastrointestinal bleeding-Computed Tomographic Angiography, Colonoscopy or both?
Lower endoscopy (LE) is the standard diagnostic modality for lower gastrointestinal bleeding (LGIB). Conversely, computed tomographic angiography (CTA) offers an immediate non-invasive diagnosis visualizing the entire gastrointestinal tract. The aim of this study was to compare these 2 modalities with regards to diagnostic value and bleeding control.
Tertiary center retrospective analysis of consecutive patients admitted for LGIB between 2006 and 2012. Comparison of patients with LE <i>vs.</i> CTA as first exam, respectively, with emphasis on diagnostic accuracy and bleeding control.
Final analysis included 183 patients; 122 (66.7%) had LE first, while 32 (17.5%) had CTA; 29 (15.8%) had neither of both exams. Median time to CTA was shorter compared to LE (3 (IQR = 8.2) <i>vs.</i> 22 (IQR = 36.9) hours, <i>P</i> < 0.001). Active bleeding was identified in 31% with CTA <i>vs.</i> 15% with LE ( <i>P</i> = 0.031); a non-actively bleeding source was found by CTA and LE in 22 <i>vs.</i> 31%, respectively ( <i>P</i> = 0.305). Bleeding control required endoscopy in 19%, surgery in 14% and embolization in 1.6%, while 66% were treated conservatively. Post-interventional bleeding was mostly controlled by endoscopic therapy (57%). 80% of patients with active bleeding on CTA required surgery.
Post-interventional LGIB was effectively addressed by LE. For other causes of LGIB, CTA was efficient, and more available than colonoscopy. Treatment was conservative for most patients. In case of active bleeding, CTA could localize the bleeding source and predict the need for surgery
Threading, Stitching, and Storytelling: Using CBPR and Blackfoot Knowledge and Cultural Practices to Improve Domestic Violence Services for Indigenous Women
This article discusses a community-based participatory research (CBPR) project at two women’s emergency shelters in rural southwestern Alberta. The CBPR project aimed to improve shelter services on and off reserve in our area by engaging the voices of Indigenous women who had experienced domestic violence. The project’s methods were participatory appraisal and arts-based work re-imagined through Blackfoot cultural practices of storytelling and shawl making. The project created a rare safe space where thirteen Blackfoot women emphasised DV services should provide opportunities to connect with family and community and role model Blackfoot knowledge. Role modelling traditional knowledges aids developing life and parenting skills, opening up pathways for Indigenous women to more positive, secure futures. These women’s recommendations impelled this article to challenge the individualized case management model and discourses of cultural competence dominating Canadian DV services, which isolate and marginalize Indigenous women when they seek help. We highlight resources existing in Blackfoot communities to manage and prevent violence by protecting and facilitating Indigenous women’s connections to their communities and cultures, and offer ways to utilize these more effectively in service settings
A P-type ATPase importer that discriminates between essential and toxic transition metals
Transition metals, although being essential cofactors in many physiological processes, are toxic at elevated concentrations. Among the membrane-embedded transport proteins that maintain appropriate intracellular levels of transition metals are ATP-driven pumps belonging to the P-type ATPase superfamily. These metal transporters may be differentiated according to their substrate specificities, where the majority of pumps can extrude either silver and copper or zinc, cadmium, and lead. In the present report, we have established the substrate specificities of nine previously uncharacterized prokaryotic transition-metal P-type ATPases. We find that all of the newly identified exporters indeed fall into one of the two above-mentioned categories. In addition to these exporters, one importer, Pseudomonas aeruginosa Q9I147, was also identified. This protein, designated HmtA (heavy metal transporter A), exhibited a different substrate recognition profile from the exporters. In vivo metal susceptibility assays, intracellular metal measurements, and transport experiments all suggest that HmtA mediates the uptake of copper and zinc but not of silver, mercury, or cadmium. The substrate selectivity of this importer ensures the high-affinity uptake of essential metals, while avoiding intracellular contamination by their toxic counterparts
Optimal investment and location decisions of a firm in a flood risk area using impulse control theory
Flooding events can affect businesses close to rivers, lakes or coasts. This paper provides an economic partial equilibrium model, which helps to understand the optimal location choice for a firm in flood risk areas and its investment strategies. How often, when and how much are firms willing to invest in flood risk protection measures? We apply Impulse Control Theory and develop a continuation algorithm to solve the model numerically. We find that, the higher the flood risk and the more the firm values the future, i.e. the more sustainable the firm plans, the more the firm will invest in flood defense. Investments in productive capital follow a similar path. Hence, planning in a sustainable way leads to economic growth. Sociohydrological feedbacks are crucial for the location choice of the firm, whereas different economic settings have an impact on investment strategies. If flood defense is already present, e.g. built up by the government, firms move closer to the water and invest less in flood defense, which allows firms to generate higher expected profits. Firms with a large initial productive capital surprisingly try not to keep their market advantage, but rather reduce flood risk by reducing exposed productive capital
Feasibility and Safety of Pressurized Intraperitoneal Aerosol Chemotherapy for Peritoneal Carcinomatosis: A Retrospective Cohort Study.
Background. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) has been introduced as a novel repeatable treatment for peritoneal carcinomatosis. The available evidence from the pioneer center suggests good tolerance and high response rates, but independent confirmation is needed. A single-center cohort was analyzed one year after implementation for feasibility and safety. Methods. PIPAC was started in January 2015, and every patient was entered into a prospective database. This retrospective analysis included all consecutive patients operated until April 2016 with emphasis on surgical feasibility and early postoperative outcomes. Results. Forty-two patients (M : F = 8 : 34, median age 66 (59-73) years) with 91 PIPAC procedures in total (4×: 1, 3×: 17, 2×: 12, and 1×: 12) were analyzed. Abdominal accessibility rate was 95% (42/44); laparoscopic access was not feasible in 2 patients with previous HIPEC. Median initial peritoneal carcinomatosis index (PCI) was 10 (IQR 5-17). Median operation time was 94 min (89-108) with no learning curve observed. One PIPAC application was postponed due to intraoperative intestinal lesion. Overall morbidity was 9% with 7 minor complications (Clavien I-II) and one PIPAC-unrelated postoperative mortality. Median postoperative hospital stay was 3 days (2-3). Conclusion. Repetitive PIPAC is feasible in most patients with refractory carcinomatosis of various origins. Intraoperative complications and postoperative morbidity rates were low. This encourages prospective studies assessing oncological efficacy
Highly restricted localization of RNA polymerase II within a locus control region of a tissue-specific chromatin domain
RNA polymerase II (Pol II) can associate with regulatory elements far from promoters. For the murine β-globin locus, Pol II binds the β-globin locus control region (LCR) far upstream of the β-globin promoters, independent of recruitment to and activation of the βmajor promoter. We describe here an analysis of where Pol II resides within the LCR, how it is recruited to the LCR, and the functional consequences of recruitment. High-resolution analysis of the distribution of Pol II revealed that Pol II binding within the LCR is restricted to the hypersensitive sites. Blocking elongation eliminated the synthesis of genic and extragenic transcripts and eliminated Pol II from the βmajor open reading frame. However, the elongation blockade did not redistribute Pol II at the hypersensitive sites, suggesting that Pol II is recruited to these sites. The distribution of Pol II did not strictly correlate with the distributions of histone acetylation and methylation. As Pol II associates with histone-modifying enzymes, Pol II tracking might be critical for establishing and maintaining broad histone modification patterns. However, blocking elongation did not disrupt the histone modification pattern of the β-globin locus, indicating that Pol II tracking is not required to maintain the pattern
What Does an Exemplary Middle School Mathematics Teacher Look Like? The Use of a Professional Development Rubric
A School University Research Network (SURN) committee composed of current mathematics teachers, central office math supervisors, building administrators, mathematicians, and mathematics educators researched numerous sources regarding best practices in mathematics instruction. The resulting professional development rubric synthesizes their findings and can serve a professional development role by providing teachers and administrators with a tool to develop clarity and consensus on best mathematics instructional practices, and how these practices are implemented in the classroom. It is also being used as a tool for cooperating teachers in their supervision of student teachers and as a reflective method for self-evaluation
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