Policing the Spectrum Commons

One of the most contested questions in spectrum policy is whether bands of spectrum left as unlicensed will fall victim to the tragedy of the commons. Advocates of increased unlicensed spectrum often downplay what enforcement measures are necessary to minimize interference and to prevent the tragedy of the commons problem. Even imposing spectrum etiquette requirements in addition to the FCC\u27s equipment certification program will fail to address this concern effectively, as the development of such measures - e.g., the requirement that devices listen before they talk - does not ensure that they will be followed. Indeed, if there are incentives for parties to cheat on the rules that prevent tragedy of the commons-type results, some cheaters are likely to emerge and thereby undermine the promise of new and innovative technologies that use unlicensed spectrum. Although the threat posed by cheaters does not undermine completely the commons model of spectrum management, it does underscore that the proponents of that model have focused almost entirely on one half of the issue. To date, these proponents have argued that unlicensed bands can facilitate technological innovation and more efficient uses of spectrum than would a purely private property-like approach. But they have not explained what the FCC should do to prevent deviation from the protocols (or certified equipment) that maximize the effectiveness of shared uses of spectrum. Moreover, tragedy of the commons-type concerns are not merely theoretical ones, as the experience with the citizen\u27s band (CB) radio demonstrated how interference caused by unauthorized uses (such as amplifiers) can undermine a previously popular use of spectrum. In the current environment, technologies like a Wi-Fi Hog, which can take control of and fully exploit a public wi-fi network - or malicious jamming by hackers - pose the same danger. This paper both underscores the need for and develops the analytical framework to guide a new model of spectrum policy for unlicensed bands. In particular, it argues that the FCC should develop a regulatory program that integrates the efforts of end user groups, interested companies, private standard setting bodies, and its own enforcement tools. In one incarnation of this approach, the FCC can ask a private body (such as the IEEE) to report back on its progress in addressing a particular issue - understanding that it may have to pick up where the body left off (either in setting or enforcing the interference mitigation measure). To be sure, we recognize that this spectrum management strategy will require considerable effort to implement, but we believe that a failure to address these issues would be the Achilles\u27 heel of the commons model of spectrum management

In Pursuit of a Next Generation Network for Public Safety Communications

In the aftermath of Hurricane Katrina, a unitary reliance on Land Mobile Radio systems (LMRs) failed public safety agencies, leaving them without any source of communications once they lost transmission capability. Unfortunately, in the wake of this tragedy, many have dusted off traditional prescriptions for improving public safety communications, such as more dedicated spectrum and more money for single-purpose LMRs (or LMRs based on technology that fails to facilitate broader functionalities). As we explain, however, both the needs underscored by Katrina and the capabilities made possible by emerging technologies call for a different strategy. In this paper, we argue that sound policy favors adoption of a next generation flexible architecture strategy for public safety communications. Such a flexible architecture embraces technological convergence and, accordingly, strives to coordinate existing LMRs, commercial terrestrial services, satellite technology, and wireless broadband systems to provide a robust, reliable, secure, and interoperable broadband communications system. Additionally, this approach would take advantage of multi-mode radios which are already a reality in most segments of the marketplace (except for public safety). Such multi-mode radios are expected to be even more robust once the recently authorized ancillary terrestrial component (ATC) of mobile satellite services becomes an option for public safety agencies. Notably, the flexible architecture that we advocate does not necessarily require additional spectrum dedicated for public safety agencies nor prohibitive financial investment in the equipment needed to use spectrum effectively. Rather, public safety agencies can leverage networks provided by commercial providers - particularly hybrid satellite and terrestrial systems - to satisfy many public safety needs in a cost-effective fashion. To advance this vision, policymakers should ensure that (1) satellite and terrestrial providers are afforded the opportunity - through pro-market and innovative spectrum policies - to develop effective offerings for public safety agencies; and (2) public safety agencies receive sufficient financial support to promote this type of a hybrid, next generation architecture

Spectrum Policy Reform and the Next Frontier of Property Rights

The scarcity of wireless spectrum reflects a costly failure of regulation. In practice, large swaths of spectrum are vastly underused or used for low value activities, but the regulatory system prevents innovative users from gaining access to such spectrum through marketplace transactions. In calling for the propertyzing of swaths of spectrum as a replacement for the current command-and-control system, many scholars have wrongfully assumed the simplicity of how such a regime would work in practice. In short, many scholars suggest that spectrum property rights can easily borrow key principles from trespass law, reasoning that since property rights work well for land, they can work well for spectrum rights as well. But as we explain, spectrum is not the same as land, and a poorly designed property rights regime for spectrum might even be worse than the legacy model of spectrum regulation. This Article addresses three central questions that confront the design and implementation of property rights in spectrum. First, it suggests how policymakers must develop a set of rights and remedies around spectrum property rights that reflect the fact that radio signals defy boundaries and can propagate in unpredictable ways. In particular, if policymakers simply created rights in spectrum and enforced them like rights in land (i.e., with injunctions for trespass), they would invite strategic behavior: spectrum speculators would buy licenses for the sole purpose of suing other licensees when their transmission systems created interference outside the permissible boundary (i.e., act as spectrum trolls). Second, it rejects the suggestion that policymakers establish a unitary property right for spectrum, arguing that policymakers should zone the spectrum by establishing different levels of protection against interference (i.e., an ability to transmit signals with more latitude) in different frequency bands. Finally, this Article discusses what institutional strategy will best facilitate the development of the property right and its enforcement, concluding that an administrative agency - be it a new one or a reformed FCC - is better positioned than a court to develop and enforce the rules governing the use of spectrum so as to facilitate technological progress and prevent parties with antiquated equipment from objecting to more efficient uses of spectrum

Spectrum Policy Reform and the Next Frontier of Property Rights

The scarcity of wireless spectrum reflects a costly failure of regulation. In practice, large swaths of spectrum are vastly underused or used for low value activities, but the regulatory system prevents innovative users from gaining access to such spectrum through marketplace transactions. In calling for the propertyzing of swaths of spectrum as a replacement for the current command-and-control system, many scholars have wrongfully assumed the simplicity of how such a regime would work in practice. In short, many scholars suggest that spectrum property rights can easily borrow key principles from trespass law, reasoning that since property rights work well for land, they can work well for spectrum rights as well. But as we explain, spectrum is not the same as land, and a poorly designed property rights regime for spectrum might even be worse than the legacy model of spectrum regulation. This Article addresses three central questions that confront the design and implementation of property rights in spectrum. First, it suggests how policymakers must develop a set of rights and remedies around spectrum property rights that reflect the fact that radio signals defy boundaries and can propagate in unpredictable ways. In particular, if policymakers simply created rights in spectrum and enforced them like rights in land (i.e., with injunctions for trespass), they would invite strategic behavior: spectrum speculators would buy licenses for the sole purpose of suing other licensees when their transmission systems created interference outside the permissible boundary (i.e., act as spectrum trolls). Second, it rejects the suggestion that policymakers establish a unitary property right for spectrum, arguing that policymakers should zone the spectrum by establishing different levels of protection against interference (i.e., an ability to transmit signals with more latitude) in different frequency bands. Finally, this Article discusses what institutional strategy will best facilitate the development of the property right and its enforcement, concluding that an administrative agency - be it a new one or a reformed FCC - is better positioned than a court to develop and enforce the rules governing the use of spectrum so as to facilitate technological progress and prevent parties with antiquated equipment from objecting to more efficient uses of spectrum

Influenza Promotes Pneumococcal Growth during Coinfection by Providing Host Sialylated Substrates as a Nutrient Source

SummaryMuch of the mortality attributed to influenza virus is due to secondary bacterial pneumonia, particularly from Streptococcus pneumoniae. However, mechanisms underlying this coinfection are incompletely understood. We find that prior influenza infection enhances pneumococcal colonization of the murine nasopharynx, which in turn promotes bacterial spread to the lungs. Influenza accelerates bacterial replication in vivo, and sialic acid, a major component of airway glycoconjugates, is identified as the host-derived metabolite that stimulates pneumococcal proliferation. Influenza infection increases sialic acid and sialylated mucin availability and enhances desialylation of host glycoconjugates. Pneumococcal genes for sialic acid catabolism are required for influenza to promote bacterial growth. Decreasing sialic acid availability in vivo by genetic deletion of the major airway mucin Muc5ac or mucolytic treatment limits influenza-induced pneumococcal replication. Our findings suggest that higher rates of disease during coinfection could stem from influenza-provided sialic acid, which increases pneumococcal proliferation, colonization, and aspiration

Nod1 signaling overcomes resistance of S. pneumoniae to opsonophagocytic killing

Airway infection by the Gram-positive pathogen Streptococcus pneumoniae (Sp) leads to recruitment of neutrophils but limited bacterial killing by these cells. Co-colonization by Sp and a Gram-negative species, Haemophilus influenzae (Hi), provides sufficient stimulus to induce neutrophil and complement-mediated clearance of Sp from the mucosal surface in a murine model. Products from Hi, but not Sp, also promote killing of Sp by ex vivo neutrophil-enriched peritoneal exudate cells. Here we identify the stimulus from Hi as its peptidoglycan. Enhancement of opsonophagocytic killing was facilitated by signaling through nucleotide-binding oligomerization domain-1 (Nod1), which is involved in recognition of γ-D-glutamyl-meso-diaminopimelic acid (meso-DAP) contained in cell walls of Hi but not Sp. Neutrophils from mice treated with Hi or compounds containing meso-DAP, including synthetic peptidoglycan fragments, showed increased Sp killing in a Nod1-dependent manner. Moreover, Nod1-/- mice showed reduced Hi-induced clearance of Sp during co-colonization. These observations offer insight into mechanisms of microbial competition and demonstrate the importance of Nod1 in neutrophil-mediated clearance of bacteria in vivo

Atomic correlations in itinerant ferromagnets: quasi-particle bands of nickel

We measure the band structure of nickel along various high-symmetry lines of the bulk Brillouin zone with angle-resolved photoelectron spectroscopy. The Gutzwiller theory for a nine-band Hubbard model whose tight-binding parameters are obtained from non-magnetic density-functional theory resolves most of the long-standing discrepancies between experiment and theory on nickel. Thereby we support the view of itinerant ferromagnetism as induced by atomic correlations.Comment: 4 page REVTeX 4.0, one figure, one tabl

Do subthreshold psychotic experiences predict clinical outcomes in unselected non-help-seeking population-based samples? A systematic review and meta-analysis, enriched with new results

Background The base rate of transition from subthreshold psychotic experiences (the exposure) to clinical psychotic disorder (the outcome) in unselected, representative and non-help-seeking population-based samples is unknown. Method A systematic review and meta-analysis was conducted of representative, longitudinal population-based cohorts with baseline assessment of subthreshold psychotic experiences and follow-up assessment of psychotic and non-psychotic clinical outcomes. Results Six cohorts were identified with a 3-24-year follow-up of baseline subthreshold self-reported psychotic experiences. The yearly risk of conversion to a clinical psychotic outcome in exposed individuals (0.56%) was 3.5 times higher than for individuals without psychotic experiences (0.16%) and there was meta-analytic evidence of dose-response with severity/persistence of psychotic experiences. Individual studies also suggest a role for motivational impairment and social dysfunction. The evidence for conversion to non-psychotic outcome was weaker, although findings were similar in direction. Conclusions Subthreshold self-reported psychotic experiences in epidemiological non-help-seeking samples index psychometric risk for psychotic disorder, with strong modifier effects of severity/persistence. These data can serve as the population reference for selected and variable samples of help-seeking individuals at ultra-high risk, for whom much higher transition rates have been indicate