Gamma-Ray Bursts from Primordial Quark Objects in Space

We investigate the possibility that gamma-ray bursts originate in a concentric spherical shell with a given average redshift and find that this is indeed compatible with the data from the third BATSE (3B) catalog. It is also shown that there is enough freedom in the choice of unknown burst properties to allow even for extremely large distances to the majority of bursts. Therefore, we speculate about an early, and very energetic, origin of bursts, and suggest that they come from phase transitions in massive objects of pure quark matter, left over from the Big Bang.Comment: 11 pages, Latex, 3 postscript figures, to be publ in the Proc of the Joint Meeting of the Networks 'The Fundamental Structure of Matter' and 'Tests of the Electroweak Symmetry Breaking', Ouranoupolis, Greece, May 199

Manifestations of Extra Dimensions in a Neutrino Telescope

Theories with large extra dimensions provide the possibility that a flavor neutrino, localized in a 3+1 brane, can mix with a singlet neutrino living in the bulk. This mixing leads to unconventional patterns of neutrino matter oscillations and we examine in details how these oscillations depend upon two parameters: the brane-bulk coupling $\xi$ and the effective mass $\mu$ of the flavor neutrino inside matter. We find that high energy $(E \ge 50$ GeV) $\nu_\mu$ neutrinos, to be detected by neutrino telescopes, can give signals of extra dimensions. With a 1 k$m^{3}$ neutrino telescope extra dimensions with radius down to $1\mu m$ can be tested directly, while for smaller radius an indirect evidence can be established.Comment: 14 pages, 5 figures, added conclusion

Patients Reasons for Choosing Office-based Buprenorphine: Preference for Patient-Centered Care

Objectives - To explore HIV-infected patients\u27 attitudes about buprenorphine treatment in office-based and opioid treatment program (OTP) settings. Methods - We conducted in-depth qualitative interviews with 29 patients with co-existing HIV infection and opioid dependence seeking buprenorphine maintenance therapy in office-based and OTP settings. We used thematic analysis of transcribed audiorecorded interviews to identify themes. Results - Patients voiced a strong preference for office-based treatment. Four themes emerged to explain this preference. First, patients perceived the greater convenience of office-based treatment as improving their ability to address HIV and other healthcare issues. Second, they perceived a strong patient-focused orientation in patient-provider relationships underpinning their preference for office-based care. This was manifest as increased trust, listening, empathy, and respect from office-based staff and providers. Third, they perceived shared power and responsibility in officebased settings. Finally, patients viewed office-based treatment as a more supportive environment for sobriety and relapse prevention. This was partly due to strong therapeutic alliances with office-based staff and providers who prioritized a harm reduction approach, but also due to the perception that the office-based settings were safer for sobriety, compared with increased opportunities for purchasing and using illicit opiates in OTP settings. Conclusions - HIV-infected patients with opioid dependence preferred office-based buprenorphine because they perceived it as offering a more patient-centered approach to care compared with OTP referral. Office-based buprenorphine may facilitate engagement in care for patients with co-existing opioid dependence and HIV infection

Neutrino tomography - Learning about the Earth's interior using the propagation of neutrinos

Because the propagation of neutrinos is affected by the presence of Earth matter, it opens new possibilities to probe the Earth's interior. Different approaches range from techniques based upon the interaction of high energy (above TeV) neutrinos with Earth matter, to methods using the MSW effect on the neutrino oscillations of low energy (MeV to GeV) neutrinos. In principle, neutrinos from many different sources (sun, atmosphere, supernovae, beams etc.) can be used. In this talk, we summarize and compare different approaches with an emphasis on more recent developments. In addition, we point out other geophysical aspects relevant for neutrino oscillations.Comment: 22 pages, 9 figures. Proceedings of ``Neutrino sciences 2005: Neutrino geophysics'', December 14-16, 2005, Honolulu, USA. Minor changes, some references added. Final version to appear in Earth, Moon, and Planet

Predictors of Opioid and Alcohol Pharmacotherapy Initiation at Hospital Discharge Among Patients Seen by an Inpatient Addiction Consult Service

Background: Medications for opioid use disorder (MOUD) and alcohol use disorder (MAUD) are effective and under-prescribed. Hospital-based addiction consult services can engage out-of-treatment adults in addictions care. Understanding which patients are most likely to initiate MOUD and MAUD can inform interventions and deepen understanding of hospitals’ role in addressing substance use disorders (SUD). Objective: Determine patient- and consult-service level characteristics associated with MOUD/MAUD initiation during hospitalization. Methods: We analyzed data from a study of the Improving Addiction Care Team (IMPACT), an interprofessional hospital-based addiction consult service at an academic medical center. Researchers collected patient surveys and clinical data from September 2015 to May 2018. We used logistic regression to identify characteristics associated with medication initiation among participants with OUD, AUD, or both. Candidate variables included patient demographics, social determinants, and treatment-related factors. Results: Three hundred thirty-nine participants had moderate to severe OUD, AUD, or both and were not engaged in MOUD/MAUD care at admission. Past methadone maintenance treatment (aOR 2.07, 95%CI (1.17, 3.66)), homelessness (aOR 2.63, 95%CI (1.52, 4.53)), and partner substance use (aOR 2.05, 95%CI (1.12, 3.76) were associated with MOUD/MAUD initiation. Concurrent methamphetamine use disorder (aOR 0.32, 95%CI (0.18, 0.56)) was negatively associated with MOUD/MAUD initiation. Conclusions: The association of MOUD/MAUD initiation with homelessness and partner substance use suggests that hospitalization may be an opportunity to reach highly-vulnerable people, further underscoring the need to provide hospital-based addictions care as a health-system strategy. Methamphetamine\u27s negative association with MOUD/MAUD warrants further study

Lessons Learned from the Implementation of a Medically Enhanced Residential Treatment (Mert) Model Integrating Intravenous Antibiotics and Residential Addiction Treatment

BACKGROUND: Hospitalizations for severe infections associated with substance use disorder (SUD) are increasing. People with SUD often remain hospitalized for many weeks instead of completing intravenous antibiotics at home; often, they are denied skilled nursing facility admission. Residential SUD treatment facilities are not equipped to administer intravenous antibiotics. We developed a medically enhanced residential treatment (MERT) model integrating residential SUD treatment and long-term IV antibiotics as part of a broader hospital-based addiction medicine service. MERT had low recruitment and retention, and ended after six months. The goal of this study was to describe the feasibility and acceptability of MERT, to understand implementation factors, and explore lessons learned. METHODS: We conducted a mixed-methods evaluation. We included all potentially eligible MERT patients, defined by those needing ≥2 weeks of intravenous antibiotics discharged from February 1 to August 1, 2016. We used chart review to identify diagnoses, antibiotic treatment location, and number of recommended and actual IV antibiotic-days completed. We audiorecorded and transcribed key informant interviews with patients and staff. We conducted an ethnographic analysis of interview transcripts and implementation field notes. RESULTS: Of the 45 patients needing long-term intravenous antibiotics, 18 were ineligible and 20 declined MERT. 7 enrolled in MERT and three completed their recommended intravenous antibiotic course. MERT recruitment barriers included patient ambivalence towards residential treatment, wanting to prioritize physical health needs, and fears of untreated pain in residential. MERT retention barriers included high demands of residential treatment, restrictive practices due to PICC lines, and perceptions by staff and other residents that MERT patients “stood out” as “different.” Despite the challenges, key informants felt MERT was a positive construct. CONCLUSIONS: Though MERT had many possible advantages; it proved more challenging to implement than anticipated. Our lessons may be applicable to future models integrating posthospital intravenous antibiotics and SUD care

Second Order Perturbations of a Macroscopic String; Covariant Approach

Using a world-sheet covariant formalism, we derive the equations of motion for second order perturbations of a generic macroscopic string, thus generalizing previous results for first order perturbations. We give the explicit results for the first and second order perturbations of a contracting near-circular string; these results are relevant for the understanding of the possible outcome when a cosmic string contracts under its own tension, as discussed in a series of papers by Vilenkin and Garriga. In particular, second order perturbations are necessaary for a consistent computation of the energy. We also quantize the perturbations and derive the mass-formula up to second order in perturbations for an observer using world-sheet time $\tau$. The high frequency modes give the standard Minkowski result while, interestingly enough, the Hamiltonian turns out to be non-diagonal in oscillators for low-frequency modes. Using an alternative definition of the vacuum, it is possible to diagonalize the Hamiltonian, and the standard string mass-spectrum appears for all frequencies. We finally discuss how our results are also relevant for the problems concerning string-spreading near a black hole horizon, as originally discussed by Susskind.Comment: New discussion about the quantum mass-spectrum in chapter

Ambulatory Intensive Care for Medically Complex Patients at a Health Care Clinic for Individuals Experiencing Homelessness The SUMMIT Randomized Clinical Trial

Importance Intensive primary care interventions have been promoted to reduce hospitalization rates and improve health outcomes for medically complex patients, but evidence of their efficacy is limited. Objective To assess the efficacy of a multidisciplinary ambulatory intensive care unit (A-ICU) intervention on health care utilization and patient-reported outcomes. Design, Setting, and Participants The Streamlined Unified Meaningfully Managed Interdisciplinary Team (SUMMIT) randomized clinical trial used a wait-list control design and was conducted at a health care clinic for patients experiencing homelessness in Portland, Oregon. The first patient was enrolled in August 2016, and the last patient was enrolled in November 2019. Included patients had 1 or more hospitalizations in the prior 6 months and 2 or more chronic medical conditions, substance use disorder, or mental illness. Data analysis was performed between March and May 2021. Intervention The A-ICU included a team manager, a pharmacist, a nurse, care coordinators, social workers, and physicians. Activities included comprehensive 90-minute intake, transitional care coordination, and flexible appointments, with reduced panel size. Enhanced usual care (EUC), consisting of team-based primary care with access to community health workers and mental health, addiction treatment, and pharmacy services, served as the comparator. Participants who received EUC joined the A-ICU intervention after 6 months. Main Outcomes and Measures The main outcome was the difference in rates of hospitalization (primary outcome), emergency department (ED) visits, and primary care physician (PCP) visits per person over 6 months (vs the prior 6 months). Patient-reported outcomes included changes in patient activation, experience, health-related quality of life, and self-rated health at 6 months (vs baseline). We performed an intention-to-treat analysis using a linear mixed-effects model with a random intercept for each patient to examine the association between study group and outcomes

Cosmic Rays and Large Extra Dimensions

We have proposed that the cosmic ray spectrum "knee", the steepening of the cosmic ray spectrum at energy E \gsim 10^{15.5} eV, is due to "new physics", namely new interactions at TeV cm energies which produce particles undetected by the experimental apparatus. In this letter we examine specifically the possibility that this interaction is low scale gravity. We consider that the graviton propagates, besides the usual four dimensions, into an additional $\delta$, compactified, large dimensions and we estimate the graviton production in $p p$ collisions in the high energy approximation where graviton emission is factorized. We find that the cross section for graviton production rises as fast as $(\sqrt{s}/M_f)^{2+\delta}$, where $M_f$ is the fundamental scale of gravity in $4+\delta$ dimensions, and that the distribution of radiating a fraction $y$ of the initial particle's energy into gravitational energy (which goes undetected) behaves as $\delta y^{\delta -1}$. The missing energy leads to an underestimate of the true energy and generates a break in the {\sl inferred} cosmic ray spectrum (the "kne"). By fitting the cosmic ray spectrum data we deduce that the favorite values for the parameters of the theory are $M_f \sim 8$ TeV and $\delta =4$.Comment: 8 pages, 1 figur

String Tension and the Generation of the Conformal Anomaly

The origin of the string conformal anomaly is studied in detail. We use a reformulated string Lagrangian which allows to consider the string tension $T_{0}$ as a small perturbation. The expansion parameter is the worldsheet speed of light c, which is proportional to $T_{0}$ . We examine carefully the interplay between a null (tensionless) string and a tensionful string which includes orders $c^{2}$ and higher. The conformal algebra generated by the constraints is considered. At the quantum level the normal ordering provides a central charge proportional to $c^{2}$. Thus it is clear that quantum null strings respect conformal invariance and it is the string tension which generates the conformal anomaly.Comment: More references are included. Final version, to appear in Phys.Rev.D. 6 pages, LaTex, no figure