Legal space for syringe exchange programs in hot spots of injection drug use-related crime.

BACKGROUND: Copious evidence indicates that syringe exchange programs (SEPs) are effective structural interventions for HIV prevention among persons who inject drugs (PWID). The efficacy of SEPs in supporting the public health needs of PWID populations is partially dependent on their accessibility and consistent utilization among injectors. Research has shown that SEP access is an important predictor of PWID retention at SEPs, yet policies exist that may limit the geographic areas where SEP operations may legally occur. Since 2000 in the District of Columbia (DC), SEP operations have been subject to the 1000 Foot Rule (§48-1121), a policy that prohibits the distribution of any needle or syringe for the hypodermic injection of any illegal drug in any area of the District of Columbia which is within 1000 feet of a public or private elementary or secondary school (including a public charter school). The 1000 Foot Rule may impede SEP services in areas that are in urgent need for harm reduction services, such as locations where injections are happening in real time or where drugs are purchased or exchanged. We examined the effects of the 1000 Foot Rule on SEP operational space in injection drug use (IDU)-related crime (i.e., heroin possession or distribution) hot spots from 2000 to 2010. METHODS: Data from the DC Metropolitan Police Department were used to identify IDU-related crime hot spots. School operation data were matched to a dataset that described the approximate physical property boundaries of land parcels. A 1000-ft buffer was applied to all school property boundaries. The overlap between the IDU-related crime hot spots and the school buffer zones was calculated by academic year. RESULTS: When overlaying the land space associated with IDU-related crime hot spots on the maps of school boundaries per the 1000-ft buffer zone stipulation, we found that the majority of land space in these locations was ineligible for legal SEP operations. More specifically, the ineligible space in the identified hot spots in each academic year ranged from 51.93 to 88.29 % of the total hot spot area. CONCLUSIONS: The removal of the 1000 Foot Rule could significantly improve the public health of PWID via increased access to harm reduction services. Buffer zone policies that restrict SEP operational space negatively affect the provision of harm reduction services to PWID

Supernova Limits on the Cosmic Equation of State

We use Type Ia supernovae studied by the High-Z Supernova Search Team to constrain the properties of an energy component which may have contributed to accelerating the cosmic expansion. We find that for a flat geometry the equation of state parameter for the unknown component, alpha_x=P_x/rho_x, must be less than -0.55 (95% confidence) for any value of Omega_m and is further limited to alpha_x<-0.60 (95%) if Omega_m is assumed to be greater than 0.1 . These values are inconsistent with the unknown component being topological defects such as domain walls, strings, or textures. The supernova data are consistent with a cosmological constant (alpha_x=-1) or a scalar field which has had, on average, an equation of state parameter similar to the cosmological constant value of -1 over the redshift range of z=1 to the present. Supernova and cosmic microwave background observations give complementary constraints on the densities of matter and the unknown component. If only matter and vacuum energy are considered, then the current combined data sets provide direct evidence for a spatially flat Universe with Omega_tot=Omega_m+Omega_Lambda = 0.94 +/- 0.26 (1-sigma).Comment: Accepted for publication in ApJ, 3 figure

Low-Frequency Oscillations in Global Simulations of Black Hole Accretion

We have identified the presence of large-scale, low-frequency dynamo cycles in a long-duration, global, magnetohydrodynamic (MHD) simulation of black hole accretion. Such cycles had been seen previously in local shearing box simulations, but we discuss their evolution over 1,500 inner disk orbits of a global pi/4 disk wedge spanning two orders of magnitude in radius and seven scale heights in elevation above/below the disk midplane. The observed cycles manifest themselves as oscillations in azimuthal magnetic field occupying a region that extends into a low-density corona several scale heights above the disk. The cycle frequencies are ten to twenty times lower than the local orbital frequency, making them potentially interesting sources of low-frequency variability when scaled to real astrophysical systems. Furthermore, power spectra derived from the full time series reveal that the cycles manifest themselves at discrete, narrow-band frequencies that often share power across broad radial ranges. We explore possible connections between these simulated cycles and observed low-frequency quasi-periodic oscillations (LFQPOs) in galactic black hole binary systems, finding that dynamo cycles have the appropriate frequencies and are located in a spatial region associated with X-ray emission in real systems. Derived observational proxies, however, fail to feature peaks with RMS amplitudes comparable to LFQPO observations, suggesting that further theoretical work and more sophisticated simulations will be required to form a complete theory of dynamo-driven LFQPOs. Nonetheless, this work clearly illustrates that global MHD dynamos exhibit quasi-periodic behavior on timescales much longer than those derived from test particle considerations.Comment: Version accepted to The Astrophysical Journal, 8 pages, 7 figure

Cosmological Magnetic Fields from Primordial Helicity

Primordial magnetic fields may account for all or part of the fields observed in galaxies. We consider the evolution of the magnetic fields created by pseudoscalar effects in the early universe. Such processes can create force-free fields of maximal helicity; we show that for such a field magnetic energy inverse cascades to larger scales than it would have solely by flux freezing and cosmic expansion. For fields generated at the electroweak phase transition, we find that the predicted wavelength today can in principle be as large as 10 kpc, and the field strength can be as large as 10^{-10} G.Comment: 13 page

Diminished trk A receptor signaling reveals cholinergic‐attentional vulnerability of aging

The cellular mechanisms underlying the exceptional vulnerability of the basal forebrain ( BF ) cholinergic neurons during pathological aging have remained elusive. Here we employed an adeno‐associated viral vector‐based RNA interference ( AAV ‐ RNA i) strategy to suppress the expression of tropomyosin‐related kinase A (trk A ) receptors by cholinergic neurons in the nucleus basalis of M eynert/substantia innominata ( nMB / SI ) of adult and aged rats. Suppression of trk A receptor expression impaired attentional performance selectively in aged rats. Performance correlated with trk A levels in the nMB / SI . trk A knockdown neither affected nMB / SI cholinergic cell counts nor the decrease in cholinergic cell size observed in aged rats. However, trk A suppression augmented an age‐related decrease in the density of cortical cholinergic processes and attenuated the capacity of cholinergic neurons to release acetylcholine ( AC h). The capacity of cortical synapses to release AC h in vivo was also lower in aged/trk A ‐ AAV ‐infused rats than in aged or young controls, and it correlated with their attentional performance. Furthermore, age‐related increases in cortical pro NGF and p75 receptor levels interacted with the vector‐induced loss of trk A receptors to shift NGF signaling toward p75‐mediated suppression of the cholinergic phenotype, thereby attenuating cholinergic function and impairing attentional performance. These effects model the abnormal trophic regulation of cholinergic neurons and cognitive impairments in patients with early A lzheimer's disease. This rat model is useful for identifying the mechanisms rendering aging cholinergic neurons vulnerable as well as for studying the neuropathological mechanisms that are triggered by disrupted trophic signaling. The cellular mechanisms underlying the exceptional vulnerability of the basal forebrain ( BF ) cholinergic neurons during pathological aging have remained elusive. Here we employed an adeno‐associated viral vector‐based RNA interference ( AAV ‐ RNA i) strategy to suppress the expression of trk A receptors by cholinergic neurons in the nucleus basalis of M eynert/substantia innominata (n MB / SI ) of adult and aged rats. This study provides novel evidence that reduced trkA receptors is not sufficient to trigger cholinergic dysfunction. Rather, aging interacts with disrupted trkA signaling to escalate the vulnerability of BF cholinergic neurons and the manifestation of age‐related attentional impairments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/96365/1/ejn12090-sup-0001-SupportingInformation.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/96365/2/ejn12090.pd

Time to Use Dendrohydrological Data in Water Resources Management?

In this editorial, we argue that the water resources management community should move away from relying only on short instrumental record, and instead incorporate long term tree-ring data into informing water management

A dynamic model of gene expression in monocytes reveals differences in immediate/early response genes between adult and neonatal cells

Neonatal monocytes display immaturity of numerous functions compared with adult cells. Gene expression arrays provide a promising tool for elucidating mechanisms underlying neonatal immune function. We used a well-established microarray to analyze differences between LPS-stimulated human cord blood and adult monocytes to create dynamic models for interactions to elucidate observed deficiencies in neonatal immune responses. We identified 168 genes that were differentially expressed between adult and cord monocytes after 45 min incubation with LPS. Of these genes, 95% (159 of 167) were over-expressed in adult relative to cord monocytes. Differentially expressed genes could be sorted into nine groups according to their kinetics of activation. Functional modelling suggested differences between adult and cord blood in the regulation of apoptosis, a finding confirmed using annexin binding assays. We conclude that kinetic studies of gene expression reveal potentially important differences in gene expression dynamics that may provide insight into neonatal innate immunity