Cross-Layer Packet Size Optimization for Wireless Terrestrial, Underwater, and Underground Sensor Networks

In this paper, a cross-layer solution for packet size optimization in wireless sensor networks (WSN) is introduced such that the effects of multi-hop routing, the broadcast nature of the physical wireless channel, and the effects of error control techniques are captured. A key result of this paper is that contrary to the conventional wireless networks, in wireless sensor networks, longer packets reduce the collision probability. Consequently, an optimization solution is formalized by using three different objective functions, i.e., packet throughput, energy consumption, and resource utilization. Furthermore, the effects of end-to-end latency and reliability constraints are investigated that may be required by a particular application. As a result, a generic, cross-layer optimization framework is developed to determine the optimal packet size in WSN. This framework is further extended to determine the optimal packet size in underwater and underground sensor networks. From this framework, the optimal packet sizes under various network parameters are determined.

Observations on Chromosomes of <i>Dicrostonyx torquatus stevensonii> Nelson and Chromosomal Diversity in Varying Lemmings = Untersuchungen an den Chromosomen von <i>Dicrostonyx torquatus stevensonii> Nelson und chromosomale Unterschiede bei Halsbandlemmingen

English abstract: The cytogenetic characteristics of the varying lemming, Dicrostonyx torquatus stevensoni, (2n = 34), were investigated, and diploid chromosomal numbers were reported for four other nominal subspecies (exsul, nelsoni, richardsoni, and rubricatus) of the torquatus-group in North America. The diploid complements ranged from 30 to 44 chromosomes, and the fundamental number from 50 to 55. Chromosomal polymorphism was observed in all forms. In cross-breeding experiments, the mating of F1 progeny was not productive. The findings support the zoogeographic concept that populations of Dicrostonyx became fragmented or displaced southward during Würm time, with relict stocks persisting in unglaciated refugia or periglacial tundra. Speciation in the isolates led to chromosomal evolution, with the result that populations spreading from refugia in post-glacial time are reproductively isolated. The torquatus-group in North America appears to be a superspecies. German title: Untersuchungen an den Chromosomen von Dicrostonyx torquatus stevensoni Nelson und chromosomale Unterschiede bei Halsbandlemmingen German abstract: Die cytogenetischen Merkmale des Halsbandlemmings, Dicrostonyx torquatus stevensoni, (2n = 34) wurden eingehend untersucht, und für vier andere nordamerikanische Unterarten der torquatus-Gruppe wurden die somatischen Chromosomensätze festgestellt. Die Chromosomenzahl der untersuchten Populationen schwankte zwischen 30 und 44, der NF (Nombre Fondamental) zwischen 50 und 55. Zuchttiere der verschiedenen Populationen wurden erfolgreich gekreuzt, aber Sterilität der F1 Unterartbastarde war typisch. Die Halsbandlemminge wiesen Karyotypenverschiedenheiten auf, die sich durch Variationen des Robertsonschen Typus, Deletionen oder möglicherweise durch perizentrische Inversionen erklären. Die Ergebnisse sprechen dafür, daß das ursprüngliche Verbreitungsgebiet von Dicrostonyx in Nordamerika durch die letzte (Würm) Vereisung getrennt wurde, und daß die Reliktpopulationen die letzte Glazial-Phase in eisfreien Refugien oder in periglazialer Tundra überlebten, wo Karyotypevolution durch lokale Anpassungsbedürfnisse gefördert wurde. Die in der Postglazialzeit aus den Refugien sich verbreitenden Populationen von Dicrostonyx scheinen reproduktiv isoliert zu sein. Die torquatus-Gruppe in Nordamerika gilt also als Superspecies.

Phi Beta Delta Presentation - Lawrence Bruner

A year ago I had the privilege of being inducted into Phi Beta Delta, and at that time I was invited to speak at the next induction ceremony, which it is my pleasure to do today. I am delighted to have this opportunity to congratulate our scholarship recipient, our new inductees, Peter Gleick, President of the Pacific Institute for Studies in Development, Environment and Security, and Merlyn Carlson, Director of the Nebraska Department of Agriculture and a member of the Governor's cabinet, on their honorary memberships in the society. I want to acknowledge Harriet Turner, Director of International affairs, for her fine work on behalf of the university and us all, and I want to thank all members of this society of international scholars for the important work you do, not only for Nebraska but, indeed, for our world.

Omaha Agri-Business Club Leadership Award Presentation

It is a real pleasure to present the 2006 Omaha Agri- Business Club Leadership Award this evening during National Agriculture Week. I commend the Omaha Agri-Business Club for establishing this fine award. We always need to celebrate the accomplishments of individuals whose leadership efforts contribute to our agricultural industry which is the backbone of Nebraska and our nation.

James A. Lake Academic Freedom Award Presentation

It is both my honor and privilege to be here today to present the James A. Lake Academic Freedom Award. I thank you for this opportunity.

LEAD Presentation

Thank you for inviting us to share with you some information about the Institute of Agriculture and Natural Resources, and what we are doing for Nebraska. As a stakeholder in Nebraska's land-grant university, you and every other Nebraskan have every right at any time to ask us what we've done for you and your neighbors lately. We welcome the question. There is so much excellent work being accomplished on this campus and throughout Nebraska that I am delighted each time I have the opportunity to talk about it. The biggest problem I find is stopping - there's always so much more to say - than there is time to say it in!

Presentation Remarks: Gamma Sigma Delta Award of Merit

I am really pleased to have this opportunity to present the 2008 Gamma Sigma Delta Award of Merit to Alan Baquet. Being here to say "Congratulations, Alan," is a special treat for me - and I do say, "Congratulations, Alan." You are very deserving of this honor.

Alumni Advisory Council Presentation - Wick Alumni Center

Folks, I'm so pleased to be here with you today to talk about the Institute of Agriculture and Natural Resources, and the exciting, valuable contributions our faculty, staff, and students are making to Nebraska and, indeed, the world. Last year an independent study found the Institute of Agriculture and Natural Resources provides a conservative 15-to-1 return on state tax dollars invested with us. We call that study the At Work for Nebraska study because well, that's what we are about.

Skeletal muscle major histocompatibility complex class I and II expression differences in adult and juvenile dermatomyositis

OBJECTIVE: To analyze major histocompatibility complex expression in the muscle fibers of juvenile and adult dermatomyositis. METHOD: In total, 28 untreated adult dermatomyositis patients, 28 juvenile dermatomyositis patients (Bohan and Peter's criteria) and a control group consisting of four dystrophic and five Pompe's disease patients were analyzed. Routine histological and immunohistochemical (major histocompatibility complex I and II, StreptoABComplex/HRP, Dakopatts) analyses were performed on serial frozen muscle sections. Inflammatory cells, fiber damage, perifascicular atrophy and increased connective tissue were analyzed relative to the expression of major histocompatibility complexes I and II, which were assessed as negatively or positively stained fibers in 10 fields (200X). RESULTS: The mean ages at disease onset were 42.0 +/- 15.9 and 7.3 +/- 3.4 years in adult and juvenile dermatomyositis, respectively, and the symptom durations before muscle biopsy were similar in both groups. No significant differences were observed regarding gender, ethnicity and frequency of organ involvement, except for higher creatine kinase and lactate dehydrogenase levels in adult dermatomyositis (p<0.050). Moreover, a significantly higher frequency of major histocompatibility complex I (96.4% vs. 50.0%, p<0.001) compared with major histocompatibility complex II expression (14.3% vs. 53.6%, p = 0.004) was observed in juvenile dermatomyositis. Fiber damage (p = 0.006) and increased connective tissue (p<0.001) were significantly higher in adult dermatomyositis compared with the presence of perifascicular atrophy (p<0.001). The results of the histochemical and histological data did not correlate with the demographic data or with the clinical and laboratory features. CONCLUSION: The overexpression of major histocompatibility complex I was an important finding for the diagnosis of both groups, particularly for juvenile dermatomyositis, whereas there was lower levels of expression of major histocompatibility complex II than major histocompatibility complex I. This finding was particularly apparent in juvenile dermatomyositis.

Cross-cultural adaptation and assessment of the reliability and validity of the Core Outcome Measures Index (COMI) for the Brazilian-Portuguese language

The use of patient-orientated questionnaires is of utmost importance in assessing the outcome of spine surgery. Standardisation, using a common set of outcome measures, is essential to aid comparisons across studies/in registries. The Core Outcome Measures Index (COMI) is a short, multidimensional outcome instrument validated for patients with spinal disorders. This study aimed to produce a Brazilian-Portuguese version of the COMI. A cross-cultural adaptation of the COMI into Brazilian-Portuguese was carried out using established guidelines. 104 outpatients with chronic LBP (> 3 months) were recruited from a Public Health Spine Medical Care Centre. They completed a questionnaire booklet containing the newly translated COMI, and other validated symptom-specific questionnaires: Oswestry Disability Index (ODI) and Roland Morris disability scale (RM), and a pain visual analogue scale. All patients completed a second questionnaire within 7-10 days to assess reproducibility. The COMI summary score displayed minimal floor and ceiling effects. On re-test, the responses for each individual domain of the COMI were within 1 category in 98% patients for the domain 'function', 96% for 'symptom-specific well-being', 97% for 'general quality of life', 99% for 'social disability' and 100% for 'work disability'. The intraclass correlation coefficients (ICC2,1) for COMI pain and COMI summary scores were 0.91-0.96, which compared favourably with the corresponding values for the RM (ICC, 0.99) and ODI (ICC, 0.98). The standard error of measurement for the COMI was 0.6, giving a "minimum detectable change" (MDC95%) of approximately 1.7 points i.e., the minimum change to be considered "real change" beyond measurement error. The COMI scores correlated as hypothesised (Rho, 0.4-0.8) with the other symptom-specific questionnaires. The reproducibility of the Brazilian-Portuguese version of the COMI was comparable to that of other language versions. The COMI scores correlated in the expected manner with existing but longer symptom-specific questionnaires suggesting good convergent validity for the COMI. The Brazilian-Portuguese COMI represents a valuable tool for Brazilian study-centres in future multicentre clinical studies and surgical registries.

Prevalence of overweight preschool children in public day care centers: a cross-sectional study

CONTEXT AND OBJECTIVE: Brazil is undergoing a period of epidemiological transition associated with demographic and nutritional changes. The prevalence of obesity is also increasing in children and is causing numerous health problems that are becoming public health issues. The aim here was to evaluate the prevalence of overweight among children of two and three years of age. DESIGN AND SETTING: Cross-sectional study in municipal day care centers in Taubate, state of Sao Paulo, Brazil. METHODS: Weight and height measurements were made on 447 preschool children forming a probabilistic randomized sample. Their body mass index (BMI) was calculated. Their nutritional status was classified using the World Health Organization reference cutoff points (2006). Their mean weight, height and BMI were compared according to their age and sex. RESULTS: The mean values for the final sample (n = 447) were as follows: mean age: 38.6 months (+/- 3.5) and Z scores for: weight/height (W/H): 0.50 (+/- 1.22); height/age: -0.03 (+/- 1.07); weight/age (W/A): 0.51 (+/- 1.23); and BMI: 0.51(+/- 1.23). The prevalence of overweight children (BMI > 1 z) was 28.86%, while the prevalence of underweight children (BMI < -2 z) was 0.89%. There were no differences in mean BMI among the two and three-year age groups (P = 0.66). CONCLUSION: A high prevalence of overweight was observed in the sample of two and three-year-old children, with practically no malnutrition, thus showing that a significant nutritional transition may already be occurring, even in medium-sized cities of developing countries.

Transcription profiling of Prss16 (Tssp) can be used to find additional peptidase genes that are candidates for self-peptide generation in the thymus

Positive selection (PS) in the thymus involves the presentation of self-peptides that are bound to MHC class II on the surface of cortical thymus epithelial cells (cTECs). Prss16 gene corresponds to one important element regulating the PS of CD4(+) T lymphocytes, which encodes Thymus-specific serine protease (Tssp), a cTEC serine-type peptidase involved in the proteolytic generation of self-peptides. Nevertheless, additional peptidase genes participating in the generation of self-peptides need to be found. Because of its role in the mechanism of PS and its expression in cTECs, the Prss16 gene might be used as a transcriptional marker to identify new genes that share the same expression profile and that encode peptidases in the thymus. To test this hypothesis, we compared the differential thymic expression of 4,500 mRNAs of wild-type (WT) C57BL/6 mice with their respective Prss16-knockout (KO) mutants by using microarrays. From these, 223 genes were differentially expressed, of which 115 had known molecular/biological functions. Four endopeptidase genes (Casp1, Casp2, Psmb3 and Tpp2) share the same expression profile as the Prss16 gene; i.e., induced in WT and repressed in KO while one endopeptidase gene, Capns1, features opposite expression profile. The Tpp2 gene is highlighted because it encodes a serine-type endopeptidase functionally similar to the Tssp enzyme. Profiling of the KO mice featured down-regulation of Prss16, as expected, along with the genes mentioned above. Considering that the Prss16-KO mice featured impaired PS, the shared regulation of the four endopeptidase genes suggested their participation in the mechanism of self-peptide generation and PS.

Electronic stopping cross sections for protons in Al2O3: an experimental and theoretical study

The electronic stopping cross section (SCS) of Al2O3 for proton beams is studied both experimentally and theoretically. The measurements are made for proton energies from 40 keV up to 1 MeV, which cover the maximum stopping region, using two experimental methods, the transmission technique at low energies (similar to 40-175 keV) and the Rutherford backscattering at high energies (approximate to 190-1000 keV). These new data reveal an increment of 16% in the SCS around the maximum stopping with respect to older measurements. The theoretical study includes electronic stopping power calculations based on the dielectric formalism and on the transport cross section (TCS) model to describe the electron excitations of Al2O3. The non-linear TCS calculations of the SCS for valence electrons together with the generalized oscillator strengths (GOS) model for the core electrons compare well with the experimental data in the whole range of energies considered.

Discovery and cross-section measurement of neutron-rich isotopes in the element range from neodymium to platinum with the FRS

Using the high-resolution performance of the fragment separator FRS at GSI we have discovered 60 new neutron-rich isotopes in the atomic number range of 60 <= Z <= 78. The new isotopes were unambiguously identified in reactions with a U-238 beam impinging on a Be target at 1 GeV/nucleon. The production cross-section for the new isotopes have been measured down to the pico-barn level and compared with predictions of different model calculations. For elements above hafnium fragmentation is the dominant reaction mechanism which creates the new isotopes, whereas fission plays a dominant role for the production of the new isotopes up to thulium. (C) 2012 Elsevier B.V. All rights reserved.

Cross-national differences in questionnaires do not necessarily reflect comparable differences in disorder prevalence

To examine whether the widely used Strengths and Difficulties Questionnaire (SDQ) can validly be used to compare the prevalence of child mental health problems cross nationally. We used data on 29,225 5- to 16-year olds in eight population-based studies from seven countries: Bangladesh, Brazil, Britain, India, Norway, Russia and Yemen. Parents completed the SDQ in all eight studies, teachers in seven studies and youth in five studies. We used these SDQ data to calculate three different sorts of "caseness indicators" based on (1) SDQ symptoms, (2) SDQ symptoms plus impact and (3) an overall respondent judgement of 'definite' or 'severe' difficulties. Respondents also completed structured diagnostic interviews including extensive open-ended questions (the Development and Well-Being Assessment, DAWBA). Diagnostic ratings were all carried out or supervised by the DAWBA's creator, working in conjunction with experienced local professionals. As judged by the DAWBA, the prevalence of any mental disorder ranged from 2.2% in India to 17.1% in Russia. The nine SDQ caseness indicators (three indicators times three informants) explained 8-56% of the cross-national variation in disorder prevalence. This was insufficient to make meaningful prevalence estimates since populations with a similar measured prevalence of disorder on the DAWBA showed large variations across the various SDQ caseness indicators. The relationship between SDQ caseness indicators and disorder rates varies substantially between populations: cross-national differences in SDQ indicators do not necessarily reflect comparable differences in disorder rates. More generally, considerable caution is required when interpreting cross-cultural comparisons of mental health, particularly when these rely on brief questionnaires.