Initial Conditions for Bubble Universes

The "bubble universes" of Coleman and De Luccia play a crucial role in string cosmology. Since our own Universe is supposed to be of this kind, bubble cosmology should supply definite answers to the long-standing questions regarding cosmological initial conditions. In particular, it must explain how an initial singularity is avoided, and also how the initial conditions for Inflation were established. We argue that the simplest non-anthropic approach to these problems involves a requirement that the spatial sections defined by distinguished bubble observers should not be allowed to have arbitrarily small volumes. Casimir energy is a popular candidate for a quantum effect which can ensure this, but [because it violates energy conditions] there is a danger that it could lead to non-perturbative instabilities in string theory. We make a simple proposal for the initial conditions of a bubble universe, and show that our proposal ensures that the system is non-perturbatively stable. Thus, low-entropy conditions can be established at the beginning of a bubble universe without violating the Second Law of thermodynamics and without leading to instability in string theory. These conditions are inherited from the ambient spacetime.Comment: Further clarifications; 28 pages including three eps files. This is the final [accepted for publication] versio

Dose-response effect of interleukin (IL)-1β, tumour necrosis factor (TNF)-α, and interferon-γ on the in vitro production of epithelial neutrophil activating peptide-78 (ENA-78), IL-8, and IL-6 by human endometrial stromal cells

Purpose: The production of epithelial neutrophil activating peptide-78 (NA-78) and the interleukins IL-8 and IL-6 by endometrial stromal cells is stimulated by pro-inflammatory interleukin-1 (IL-1) and tumour necrosis factor-α (TNF-α). IL-8 is suggested to play a role in the pathogenesis of endometriosis, and in these women the peritoneal fluid concentrations of ENA-78 and IL-8 are increased. TNF-α has been tested together with interferon-γ because of their cooperative stimulation of IL-6. The release of IL-8, however, is inhibited with increasing interferon levels. The aim of the study was the analysis of the production of ENA-78, IL-6 and IL-8 by cultured human endometrial stromal cells in the presence of varying concentrations of IL-1β, TNF-α, and interferon-γ. Methods: Eutopic endometrial tissue was obtained from seven cycling, endometriosis-free women undergoing laparoscopy for reasons of infertility or pain. The release of ENA-78, IL-8 and IL-6 by the isolated and monolayer cultured stromal cell fraction in the presence of IL-1β (0.08 to 50ng/mL), TNF-α, and interferon-γ (both 20 to 500ng/mL) was determined. Results: IL-1β stimulated the production of IL-8, IL-6, and ENA-78 dose dependently from 0.08 to 2.0ng/mL (ENA-78) or to 10ng/mL (IL-8, IL-6); at 50ng/mL a decrease in release was observed for IL-8 and IL-6. TNF-α stimulation yielded a plateau between 20 and 100ng/mL. Interferon-γ stimulated IL-6 and inhibited IL-8 production above 20ng/mL. ENA-78 release was largely unaffected by interferon-γ. Conclusions: IL-1β and TNF-α stimulate stromal cytokine production cumulatively with different dose-response curves. The presence of interferon-γ has opposite effects on IL-8 and IL-6. TNF-α and interferon-γ should be investigated separately in future in vitro studies with endometrial cells and explant

Sacral Stress Fracture — Wrestling

CASE HISTORY: During preseason, a 35-year-old wrestler complained of pain in his lower back concurrently with a tingling sensation in the left thigh and buttocks. PHYSICAL EXAM: The wrestler was examined by a physical therapist (PT) and, while discussing prior medical history, the athlete mentioned a previous diagnosis of a mild herniated disk (Grade 1). Upon clinical examination, the athlete demonstrated a full range of motion with some discomfort in passive hip extension. The PT suggested rest and rehabilitation through electrical stimulation, alongside the strengthening of the lumbar spine and hip abductor muscles. Ten days later, the athlete presented to an orthopedic surgeon (Ortho) complaining of the same discomfort. During the examination, the Ortho noticed the same localized tenderness over the left sacroiliac joint. Results for both the Lasegue and FABER tests were negative. Although there was no significant sign of fracture or edema, the Ortho suggested obtaining lumbar and pelvis X-Rays. He prescribed anti-inflammatory medication and performed a corticosteroid injection in the left sacroiliac joint. After treatment, the athlete had immediate relief and was able to compete the following day in his competitive event. One week later, the athlete returned to the outpatient clinic complaining that the pain was still localized in the left sacroiliac joint. The Ortho performed the hop test, which was positive. The athlete was then referred for an MRI of the spine and pelvis followed by a CT scan. DIFFERENTIAL DIAGNOSIS: 1. Spinal Disc Herniation Aggravation; 2. Sacroiliac Joint Misalignment; 3. Sciatic Neuritis; 4. Musculotendinous Strain; and 5. Sarcoma. TESTS & RESULTS: X-Ray: Clear; Hop test: Positive; MRI: a) Lumbar region: Mild L5-S1 herniation (Grade 1) with the lumbar spine curvature found to be within normal limits and b) Pelvis: Edema with associated marrow changes due to a non-displaced sacral stress fracture; CT Scan: Fracture line along with sclerosis parallel to the sacroiliac joint. FINAL DIAGNOSIS: Stress fracture on the left, anterior column of the sacrum. DISCUSSION: Clear X-Rays are associated with 20%-38% of misdiagnoses of sacral fractures. When a stress fracture is suspected, MRI should be the indicated exam, followed by a CT scan. Our clinical case gives an indication of the decision-making process so that other physicians can apply lateral thinking to their own cases. OUTCOME OF THE CASE: 1. Rehabilitation: Rest and light weight-bearing exercises (4 months) and 2. Anti-osteoporotic treatment: Calcium and Vitamin D. RETURN TO ACTIVITY AND FURTHER FOLLOW-UP: Return to participation: 5-12 months

Knowledge and attitudes of men to prostate cancer

Objective: To ascertain the current level of understanding about prostate cancer (PCa), including treatment options and potential side effects of treatment, among older men. Design and Setting: Questionnaires administered by general practitioners (GPs) in 5 general practices in the Perth metropolitan and regional areas of Western Australia. Participants: Convenience sample of men aged 40-80 years (n=503) with or without prostate cancer presenting for routine consultations. Main outcome measures: Knowledge and attitudes of men to prostate cancer Results: Eighty percent of men did not know the function of the prostate and 48% failed to identify PCa as the most common internal cancer in men. Thirty-five percent had no knowledge of the treatments for PCa and 53% had no knowledge of the side effects of treatments. Asked how they would arrive at a decision about treatment, 70% stated they would ask the GP/specialist for all their options and then decide themselves. Conclusion: This study confirms a deficit in knowledge of the disease among men in the at risk age group. Lack of knowledge encompassed areas which could delay diagnosis and hence treatment. Overall the population preferred some GP/specialist involvement in treatment decision making

A Putative Gene Cluster from a Lyngbya wollei Bloom that Encodes Paralytic Shellfish Toxin Biosynthesis

Saxitoxin and its analogs cause the paralytic shellfish-poisoning syndrome, adversely affecting human health and coastal shellfish industries worldwide. Here we report the isolation, sequencing, annotation, and predicted pathway of the saxitoxin biosynthetic gene cluster in the cyanobacterium Lyngbya wollei. The gene cluster spans 36 kb and encodes enzymes for the biosynthesis and export of the toxins. The Lyngbya wollei saxitoxin gene cluster differs from previously identified saxitoxin clusters as it contains genes that are unique to this cluster, whereby the carbamoyltransferase is truncated and replaced by an acyltransferase, explaining the unique toxin profile presented by Lyngbya wollei. These findings will enable the creation of toxin probes, for water monitoring purposes, as well as proof-of-concept for the combinatorial biosynthesis of these natural occurring alkaloids for the production of novel, biologically active compounds

Genomic reconstruction of a novel, deeply branched sediment archaeal phylum with pathways for acetogenesis and sulfur reduction

Marine and estuary sediments contain a variety of uncultured archaea whose metabolic and ecological roles are unknown. De novo assembly and binning of high-throughput metagenomic sequences from the sulfate–methane transition zone in estuary sediments resulted in the reconstruction of three partial to near-complete (2.4–3.9 Mb) genomes belonging to a previously unrecognized archaeal group. Phylogenetic analyses of ribosomal RNA genes and ribosomal proteins revealed that this group is distinct from any previously characterized archaea. For this group, found in the White Oak River estuary, and previously registered in sedimentary samples, we propose the name ‘Thorarchaeota'. The Thorarchaeota appear to be capable of acetate production from the degradation of proteins. Interestingly, they also have elemental sulfur and thiosulfate reduction genes suggesting they have an important role in intermediate sulfur cycling. The reconstruction of these genomes from a deeply branched, widespread group expands our understanding of sediment biogeochemistry and the evolutionary history of Archaea

Reconstructing metabolic pathways of hydrocarbon-degrading bacteria from the Deepwater Horizon oil spill

The Deepwater Horizon blowout in the Gulf of Mexico in 2010, one of the largest marine oil spills1, changed bacterial communities in the water column and sediment as they responded to complex hydrocarbon mixtures2-4. Shifts in community composition have been correlated to the microbial degradation and use of hydrocarbons2,5,6, but the full genetic potential and taxon-specific metabolisms of bacterial hydrocarbon degraders remain unresolved. Here, we have reconstructed draft genomes of marine bacteria enriched from sea surface and deep plume waters of the spill that assimilate alkane and polycyclic aromatic hydrocarbons during stable-isotope probing experiments, and we identify genes of hydrocarbon degradation pathways. Alkane degradation genes were ubiquitous in the assembled genomes. Marinobacter was enriched with n-hexadecane, and uncultured Alpha- and Gammaproteobacteria populations were enriched in the polycyclic-aromatic-hydrocarbon-degrading communities and contained a broad gene set for degrading phenanthrene and naphthalene. The repertoire of polycyclic aromatic hydrocarbon use varied among different bacterial taxa and the combined capabilities of the microbial community exceeded those of its individual components, indicating that the degradation of complex hydrocarbon mixtures requires the non-redundant capabilities of a complex oil-degrading community

Aortic valve stenotic area calculation from phase contrast cardiovascular magnetic resonance: the importance of short echo time

<p>Abstract</p> <p>Background</p> <p>Cardiovascular magnetic resonance (CMR) can potentially quantify aortic valve area (AVA) in aortic stenosis (AS) using a single-slice phase contrast (PC) acquisition at valve level: AVA = aortic flow/aortic velocity-time integral (VTI). However, CMR has been shown to underestimate aortic flow in turbulent high velocity jets, due to intra-voxel dephasing. This study investigated the effect of decreasing intra-voxel dephasing by reducing the echo time (TE) on AVA estimates in patients with AS.</p> <p>Method</p> <p>15 patients with moderate or severe AS, were studied with three different TEs (2.8 ms/2.0 ms/1.5 ms), in the main pulmonary artery (MPA), left ventricular outflow tract (LVOT) and 0 cm/1 cm/2.5 cm above the aortic valve (AoV). PC estimates of stroke volume (SV) were compared with CMR left ventricular SV measurements and PC peak velocity, VTI and AVA were compared with Doppler echocardiography. CMR estimates of AVA obtained by direct planimetry from cine acquisitions were also compared with the echoAVA.</p> <p>Results</p> <p>With a TE of 2.8 ms, the mean PC SV was similar to the ventricular SV at the MPA, LVOT and AoV_{0 cm}(by Bland-Altman analysis bias ± 1.96 SD, 1.3 ± 20.2 mL/-6.8 ± 21.9 mL/6.5 ± 50.7 mL respectively), but was significantly lower at AoV₁and AoV_2.5(-29.3 ± 31.2 mL/-21.1 ± 35.7 mL). PC peak velocity and VTI underestimated Doppler echo estimates by approximately 10% with only moderate agreement. Shortening the TE from 2.8 to 1.5 msec improved the agreement between ventricular SV and PC SV at AoV_{0 cm}(6.5 ± 50.7 mL vs 1.5 ± 37.9 mL respectively) but did not satisfactorily improve the PC SV estimate at AoV_{1 cm}and AoV_{2.5 cm}. Agreement of CMR AVA with echoAVA was improved at TE 1.5 ms (0.00 ± 0.39 cm²) versus TE 2.8 (0.11 ± 0.81 cm²). The CMR method which agreed best with echoAVA was direct planimetry (-0.03 cm²± 0.24 cm²).</p> <p>Conclusion</p> <p>Agreement of CMR AVA at the aortic valve level with echo AVA improves with a reduced TE of 1.5 ms. However, flow measurements in the aorta (AoV 1 and 2.5) are underestimated and 95% limits of agreement remain large. Further improvements or novel, more robust techniques are needed in the CMR PC technique in the assessment of AS severity in patients with moderate to severe aortic stenosis.</p