9,322 research outputs found
Mathematical algorithm to transform digital biomass distribution maps into linear programming networks in order to optimize bio-energy delivery chains
Many linear programming models have been developed to model the logistics of bio-energy chains. These models help to determine the best set-up of bio-energy chains. Most of them use network structures built up from nodes with one or more depots, and arcs connecting these depots. Each depot is source of a certain biomass type. Nodes can also be a storage point for a certain biomass type or a production facility (e.g. power plant) where the biomass is used. Arcs represent transport between depots. To be able to combine GIS spatial studies with linear programming models it is necessary to build a network from a digital map. In this work a mathematical calculation method is developed to select the actual points on the map where to collect biomass that will then be considered as biomass sources in a network model
Modeling Helical Structures in Relativistic Jets
Many jets exhibit twisted helical structures. Where superluminal motions are
detected, jet orientation and pattern/flow speed are considerably constrained.
In this case modeling efforts can place strong limits on conditions in the jet
and in the external environment. This can be done by modeling the spatial
development of helical structures which are sensitively dependent on these
conditions. Along an expanding jet this sensitivity manifests itself in
predictable changes in pattern speed and observed wavelength. In general,
twists of low frequency relative to the local resonant frequency are advected
along the expanding jet into a region in which the twist frequency is high
relative to the local resonant frequency. The wave speed can be very different
in these two frequency regimes. Potential effects include helical twists with a
nearly constant apparent wavelength, an apparent wavelength scaling
approximately with the jet radius for up to two orders of magnitude of jet
expansion, or multiple twist wavelengths with vastly different intrinsic scale
and vastly different wave speeds that give rise to similar observed twist
wavelengths but with very different observed motion. In this paper I illustrate
the basic intrinsic and observed behavior of these structures and show how to
place constraints on jet conditions in superluminal jets using the apparent
structures and motions in the inner 3C 120 jet.Comment: 18 pages, 7 figure
Eksistensi Lembaga Penyiaran Publik Radio Republik Indonesia Entikong dalam Upaya Meningkatkan Wawasan Kebangsaan Masyarakat Perbatasan Entikong Kalimantan Barat dan Warga Indonesia di Tebedu Malaysia
Pemerintah Indonesia belum mampu mewujudkan implementasi penguatan penyiaran yang signifikan di wilayah perbatasan Entikong Kabupaten Sanggau, yang merupakan salah satu dari 5 wilayah perbatasan yang ada di Kalimantan Barat. Berbagai alasan dan sebab mengapa wilayah perbatasan ini sangat tertinggal dibandingkan dengan daerah lain, satu diantaranya adalah karena wilayah perbatasan negara hanya dilihat semata-mata sebagai batas wilayah (territory). Dibidang penyiaran Kecamatan Entikong hanya memiliki satu lembaga penyiaran yang beroperasi yakni LPP RRI yang mulai siaran pada tahun 2008, bandingkan dengan Malaysia yang memiliki 13 stasiun penyiaran radio dan 3 stasiun penyiaran televisi. Siaran radio dan televisi Malaysia setiap hari di dengar oleh warga perbatasan Entikong dan warga Indonesia di Tebedu Sarawak dengan jelas selama bertahun-tahun. Sehingga membuat mereka paham dengan nama-nama tokoh pejabat, Perdana Menteri dan perkembangan yang terjadi di negara Malaysia dari pada negara Indonesia disebabkan mereka telah bertahun-tahun hidup dalam dinamika yang penuh Kemalysiaan, namun semangat dan wawasan kebangsaan tetap tumbuh dan tidak terkikis zaman
Extreme photo-polarimetric behaviour of the blazar AO 0235+164
We present optical photo-polarimetric observations with high temporal
resolution of the blazar AO 0235+164. Our data, the first to test the
photo-polarimetric behaviour of this object at very short time-scales, show
significant micro-variability in total flux, colour index, linear polarization
degree, and position angle. Strong inter-night variations are also detected for
these parameters. Although no correlation between colour index and total flux
was found, our data seem to support the general bluer-when-brighter trend
already known for this object. The polarization degree, in turn, shows no
correlation with total flux, but a clear trend in the sense that colour index
is redder (the spectrum is softer) when the measured polarization is higher.Comment: Accepted by MNRAS (Letters), 5 page
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When do Theories Become Self-fulfilling? Exploring The Boundary Conditions of Performativity
Management researchers increasingly realize that some theories do not merely describe, but also shape social reality; a phenomenon known as "performativity." However, when theories become performative or even self-fulfilling is still poorly understood. Taking this gap in the research as our starting point, we develop a process model to show that new theories will only become self-fulfilling (1) if they motivate experimentation, (2) if experimentation produces anomalies, and (3) if these anomalies lead to a practice shift. On that basis, we identify six boundary conditions that determine whether theories will shape social reality. To illustrate our argument, we explore the conditions under which theories that postulate a positive link between corporate social performance and corporate financial performance may become self-fulfilling
Relationship between depressive symptom severity and emergency department use among low-income, depressed homebound older adults aged 50 years and older
Namkee G. Choi, and C. Nathan Marti are with The University of Texas at Austin, Austin, TX, USA. -- Martha L. Bruce is with the Weill Cornell Medical College, White Plains, NY, USA. -- Mark E. Kunik is with the VA HSRD Houston Center of Excellence, Michael E. DeBakey VA Medical Center, Houston, TX, USA, and Baylor College of Medicine, Houston, TX, USA, and VA South Central Mental Illness Research, Education and Clinical Center, Houston, TX, USA.Background: Previous research found a high prevalence of depression, along with chronic illnesses and disabilities, among older ED patients. This study examined the relationship between depressive symptom severity and the number of ED visits among low-income homebound older adults who participated in a randomized controlled trial of telehealth problem-solving therapy (PST).
Methods: The number of and reasons for ED visits were collected from the study participants (n=121 at baseline) at all assessment points—baseline and 12- and 24-week follow-ups. Depressive symptoms were measured with the 24-item Hamilton Rating Scale for Depression (HAMD). All multivariable analyses examining the relationships between ED visits and depressive symptoms were conducted using zero-inflated Poisson regression models.
Results: Of the participants, 67.7% used the ED at least once and 61% of the visitors made at least one return visit during the approximately 12-month period. Body pain (not from fall injury and not including chest pain) was the most common reason. The ED visit frequency at baseline and at follow-up was significantly positively associated with the HAMD scores at the assessment points. The ED visit frequency at follow-up, controlling for the ED visits at baseline, was also significantly associated with the HAMD score change since baseline.
Conclusions: The ED visit rate was much higher than those reported in other studies. Better education on self-management of chronic conditions, depression screening by primary care physicians and ED, and depression treatment that includes symptom management and problem-solving skills may be important to reduce ED visits among medically ill, low-income homebound adults.
Trial registration
ClinicalTrials.gov Identifier: NCT00903019Psycholog
First record of Aedes aegypti (L.) (Diptera: Culicidae) infected by the parasite Ascogregarina culicis (Ross) (Apicomplexa: Lecudinidae) in Argentina
n a survey for parasites and pathogens of Aedes aegypti conducted in La Plata, Argentina, an aseptate gregarine was found parasitizing larvae, pupae and adults of this mosquito species. This gregarine species was identified as Ascogregarina culicis based on the morphology and size of gamonts, gametocysts and oocysts. It is the first record of gregarine infections in culicids from ArgentinaFil: DellapĂ©, Mariana E.. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Centro de Estudios ParasitolĂłgicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios ParasitolĂłgicos y de Vectores; ArgentinaFil: Marti, Gerardo Anibal. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Centro de Estudios ParasitolĂłgicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios ParasitolĂłgicos y de Vectores; ArgentinaFil: Tranchida, Maria Cecilia. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Centro de Estudios ParasitolĂłgicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios ParasitolĂłgicos y de Vectores; ArgentinaFil: Garcia, Juan Jose. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Centro de Estudios ParasitolĂłgicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios ParasitolĂłgicos y de Vectores; Argentin
Relative pleopod length as an indicator of size at sexual maturity in slipper (Scyllarides squammosus) and spiny Hawaiian (Panulirus marginatus) lobsters
Body size at gonadal maturity is described for females of the slipper lobster (Scyllarides squammosus) (Scyllaridae) and the endemic Hawaiian spiny lobster (Panulirus marginatus) (Palinuridae) based on microscopic examination
of histological preparations of ovaries. These data are used to validate several morphological metrics (relative
exopodite length, ovigerous condition) of functional sexual maturity. Relative exopodite length (“pleopod length”) produced consistent estimates of size at maturity when evaluated with a newly derived statistical application for estimating size at the morphometric maturation point (MMP) for the population, identified as the midpoint of a sigmoid
function spanning the estimated boundaries of overlap between the largest immature and smallest adult animals.
Estimates of the MMP were related to matched (same-year) characterizations of sexual maturity based on ovigerous
condition — a more conventional measure of functional maturity previously used to characterize maturity for the two lobster species. Both measures of functional maturity were similar for the respective species and were within 5% and 2% of one another for slipper and spiny lobster,
respectively. The precision observed for two shipboard collection series of pleopod-length data indicated that the
method is reliable and not dependent on specialized expertise. Precision of maturity estimates for S. squammosus with the pleopod-length metric was similar
to that for P. marginatus with any of the other measures (including conventional evidence of ovigerous condition)
and greatly exceeded the precision of estimates for S. squammosus based on ovigerous condition alone. The two
measures of functional maturity averaged within 8% of the estimated size at gonadal maturity for the respective species. Appendage-to-body size proportions, such as the pleopod length metric, hold great promise, particularly for species of slipper lobsters like S. squammosus for which there exist no other reliable conventional morphological measures of sexual maturity. Morphometric proportions
also should be included among the factors evaluated when assessing size at sexual maturity in spiny lobster stocks;
previously, these proportions have been obtained routinely only for brachyuran crabs within the Crustacea
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