Subclasses of Presburger Arithmetic and the Weak EXP Hierarchy

It is shown that for any fixed $i>0$, the $\Sigma_{i+1}$-fragment of Presburger arithmetic, i.e., its restriction to $i+1$ quantifier alternations beginning with an existential quantifier, is complete for $\mathsf{\Sigma}^{\mathsf{EXP}}_{i}$, the $i$-th level of the weak EXP hierarchy, an analogue to the polynomial-time hierarchy residing between $\mathsf{NEXP}$ and $\mathsf{EXPSPACE}$. This result completes the computational complexity landscape for Presburger arithmetic, a line of research which dates back to the seminal work by Fischer & Rabin in 1974. Moreover, we apply some of the techniques developed in the proof of the lower bound in order to establish bounds on sets of naturals definable in the $\Sigma_1$-fragment of Presburger arithmetic: given a $\Sigma_1$-formula $\Phi(x)$, it is shown that the set of non-negative solutions is an ultimately periodic set whose period is at most doubly-exponential and that this bound is tight.Comment: 10 pages, 2 figure

The period gene encodes a predominantly nuclear protein in adult Drosophila

The period gene of Drosophila melanogaster (per) is important for the generation and maintenance of biological rhythms. Previous light microscopic observations indicated that per is expressed in a variety of tissues and cell types and suggested that the per protein (PER) may be present in different subcellular compartments. To understand how PER influences circadian rhythms, it is important to define its subcellular location, especially in adult flies where inducible promoter experiments suggested that it is most relevant to circadian locomotor activity rhythms. To this end, we report the results of an immunoelectron microscopic analysis of wild-type flies and per-beta- galactosidase (beta-gal) fusion gene transgenics using a polyclonal anti-PER antibody or an anti-beta-gal antibody, respectively. Most of the PER antigen and the fusion gene product were located within nuclei, suggesting that PER acts in that subcellular compartment to affect circadian rhythms. The results are discussed in terms of per's possible biochemical functions

Transient Mathematical Modeling for Liquid Rocket Engine Systems: Methods, Capabilities, and Experience

The subject of mathematical modeling of the transient operation of liquid rocket engines is presented in overview form from the perspective of engineers working at the NASA Marshall Space Flight Center. The necessity of creating and utilizing accurate mathematical models as part of liquid rocket engine development process has become well established and is likely to increase in importance in the future. The issues of design considerations for transient operation, development testing, and failure scenario simulation are discussed. An overview of the derivation of the basic governing equations is presented along with a discussion of computational and numerical issues associated with the implementation of these equations in computer codes. Also, work in the field of generating usable fluid property tables is presented along with an overview of efforts to be undertaken in the future to improve the tools use for the mathematical modeling process

The period gene encodes a predominantly nuclear protein in adult Drosophila

The period gene of Drosophila melanogaster (per) is important for the generation and maintenance of biological rhythms. Previous light microscopic observations indicated that per is expressed in a variety of tissues and cell types and suggested that the per protein (PER) may be present in different subcellular compartments. To understand how PER influences circadian rhythms, it is important to define its subcellular location, especially in adult flies where inducible promoter experiments suggested that it is most relevant to circadian locomotor activity rhythms. To this end, we report the results of an immunoelectron microscopic analysis of wild-type flies and per-beta- galactosidase (beta-gal) fusion gene transgenics using a polyclonal anti-PER antibody or an anti-beta-gal antibody, respectively. Most of the PER antigen and the fusion gene product were located within nuclei, suggesting that PER acts in that subcellular compartment to affect circadian rhythms. The results are discussed in terms of per's possible biochemical functions

In Utero Exposure to Environmental Tobacco Smoke Potentiates Adult Responses to Allergen in BALB/c Mice

BACKGROUND: Fetal stress has been linked to adult atherosclerosis, obesity, and diabetes. Epidemiology studies have associated fetal exposure to maternal smoking and postnatal exposure to environmental tobacco smoke (ETS) with increased asthma risk. OBJECTIVE: We tested the hypothesis, in a mouse model of asthma, that in utero ETS exposure alters airway function and respiratory immune responses in adults. METHODS: Pregnant Balb/c mice were exposed daily to ETS or HEPA-filtered air (AIR). Offspring inhaled aerosolized ovalbumin (OVA) or saline in weeks 7–8. Regardless of whether they inhaled OVA or saline, mice were sensitized by OVA injections in weeks 11 and 13 followed by OVA aerosol challenge in weeks 14–15. At three time points, we assessed OVA-specific serum immunoglobins, bronchoalveolar lavage cells and cytokines, lung and nasal histopathology, and airway hyperresponsiveness (AHR). RESULTS: At 6 weeks, we found no significant differences between in utero ETS and AIR mice. At 10 weeks, following OVA aerosol, ETS mice displayed greater AHR than AIR mice (α = 0.05), unaccompanied by changes in histopathology, cytokine profile, or antibody levels. At 15 weeks, mice that had inhaled saline in weeks 7–8 developed airway inflammation: eosinophilia (α = 0.05), interleukin-5 (α = 0.05), and AHR (α = 0.05) were greater in ETS mice than in AIR mice. Mice that had inhaled OVA in weeks 7–8 demonstrated no airway inflammation after sensitization and challenge. CONCLUSION: In utero ETS exposure exacerbates subsequent adult responses to initial allergen exposure

Living with AIDS in Uganda: a qualitative study of patients' and families' experiences following referral to hospice

Background: Globally, the majority of people with HIV/AIDS live in sub-Saharan Africa. While the increasing availability of antiretroviral therapy is improving the outlook for many, its effects are yet to reach all of those in need and patients still present with advanced disease. This paper reports findings from qualitative interviews with patients living with AIDS and their caregivers who were receiving palliative care from Hospice Africa Uganda (HAU). We aimed to understand what motivated patients and their families to seek formal healthcare, whether there were any barriers to help- seeking and how the help and support provided to them by HAU was perceived. Methods: We invited patients with AIDS and their relatives who were newly referred to HAU to participate in qualitative interviews. Patients and carers were interviewed in their homes approximately four weeks after the patient’s enrolment at HAU. Interviews were translated, transcribed and analysed using narrative and thematic approaches. Results: Interviews were completed with 22 patients (10 women and 12 men) and 20 family caregivers, nominated by patients. Interviews revealed the extent of suffering patients endured and the strain that family caregivers experienced before help was sought or accessed. Patients reported a wide range of severe physical symptoms. Patients and their relatives reported worries about the disclosure of the AIDS diagnosis and fear of stigma. Profound poverty framed all accounts. Poverty and stigma were, depending on the patient and family situation, both motivators and barriers to help seeking behaviour. Hospice services were perceived to provide essential relief of pain and symptoms, as well as providing rehabilitative support and a sense of caring. The hospice was perceived relieve utter destitution, although it was unable to meet all the expectations that patients had. Conclusion: Hospice care was highly valued and perceived to effectively manage problems such as pain and other symptoms and to provide rehabilitation. Participants noted a strong sense of being “cared for”. However, poverty and a sense of stigma were widespread. Further research is needed to understand how poverty and stigma can be effectively managed in hospice care for patients for advanced AIDS and their families

Structure of Fat Jets at the Tevatron and Beyond

Boosted resonances is a highly probable and enthusiastic scenario in any process probing the electroweak scale. Such objects when decaying into jets can easily blend with the cornucopia of jets from hard relative light QCD states. We review jet observables and algorithms that can contribute to the identification of highly boosted heavy jets and the possible searches that can make use of such substructure information. We also review previous studies by CDF on boosted jets and its measurements on specific jet shapes.Comment: invited review for a special "Top and flavour physics in the LHC era" issue of The European Physical Journal C, we invite comments regarding contents of the review; v2 added references and institutional preprint number

The behaviour of political parties and MPs in the parliaments of the Weimar Republic

Copyright @ 2012 The Authors. This is the author's accepted manuscript. The final published article is available from the link below.Analysing the roll-call votes of the MPs of the Weimar Republic we find: (1) that party competition in the Weimar parliaments can be structured along two dimensions: an economic left–right and a pro-/anti-democratic. Remarkably, this is stable throughout the entire lifespan of the Republic and not just in the later years and despite the varying content of votes across the lifespan of the Republic, and (2) that nearly all parties were troubled by intra-party divisions, though, in particular, the national socialists and communists became homogeneous in the final years of the Republic.Zukunftskolleg, University of Konstan