137 research outputs found
International Entrepreneuship and Geographic Location: An Empirical Examination of New Venture Internationalization
In this paper, we argue that geographic location may be one reason why some ventures are able to acquire the resources needed to internationalize while others cannot. We use ecological arguments to predict an inverted U-shaped relationship between the concentration of industry clustering within a geographic location and the venture\u27s internationalization. We also explore whether venture characteristics influence the nature of this relationship. Our hypotheses are regressed on international intensity and scope, and analyzed through a sample of 156 publicly held new ventures. Results confirm that location influences new venture internationalization, and firm characteristics impact the nature of the relationship
Entrepreneurial Orientation and International Scope: The Differential Roles of Innovativeness, Proactiveness, and Risk-Taking
This research integrates the international business and entrepreneurship literatures by examining the independent influences of innovativeness, proactiveness, and risk-taking on the ability of a firm to broaden its scope across international markets. For each dimension of entrepreneurial orientation, a cost–benefit framework is applied to highlight the trade-offs associated with different levels in the internationalization context. Based on a unique dataset of 500 SMEs spanning 10 industries, the results reflect the consequences of being “stuck in the middle” with respect to their strategic posture on innovativeness and proactiveness, but reveal a nuanced role for risk-taking behavior. The non-uniform and non-linear relationships from the findings contribute to a better understanding of when the individual dimensions of entrepreneurial orientation help or hinder entrepreneurial firms in the internationalization process
Ascorbate-dependent vasopressor synthesis: a rationale for vitamin C administration in severe sepsis and septic shock?
Severe systemic inflammatory response to infection results in severe sepsis and septic shock, which are the leading causes of death in critically ill patients. Septic shock is characterised by refractory hypotension and is typically managed by fluid resuscitation and administration of catecholamine vasopressors such as norepinephrine. Vasopressin can also be administered to raise mean arterial pressure or decrease the norepinephrine dose. Endogenous norepinephrine and vasopressin are synthesised by the copper-containing enzymes dopamine β-hydroxylase and peptidylglycine α-amidating monooxygenase, respectively. Both of these enzymes require ascorbate as a cofactor for optimal activity. Patients with severe sepsis present with hypovitaminosis C, and pre-clinical and clinical studies have indicated that administration of high-dose ascorbate decreases the levels of pro-inflammatory biomarkers, attenuates organ dysfunction and improves haemodynamic parameters. It is conceivable that administration of ascorbate to septic patients with hypovitaminosis C could improve endogenous vasopressor synthesis and thus ameliorate the requirement for exogenously administered vasopressors. Ascorbate-dependent vasopressor synthesis represents a currently underexplored biochemical mechanism by which ascorbate could act as an adjuvant therapy for severe sepsis and septic shock
Økologisk mjølkeproduksjon uten kraftfôr
Det er økende interesse hos forbrukere for mjølk og mjølkeprodukt som er produsert uten bruk av kraftfôr med bare beite og konservert gras i fôrrasjonen. Rørosmeieriet AS, som foredler økologisk produsert mjølk, er interessert i å etablere egen produksjonslinje for mjølkeprodukt fra kyr produsert uten kraftfôr. For mjølkeprodusenten kan det å kutte ut kraftfôr i fôrrasjonen få store konsekvenser for mjølkeytelse og dermed økonomi. Formålet med dette arbeidet var å vurdere hva en kan forvente seg av mjølkeytelse og mjølkekvalitet ved å kutte ut kraftfôr i rasjonen. Helse og fruktbarhet hos dyra, næringsstofforsyning til gården og totaløkonomien vil sannsynligvis også påvirkes, og det var et mål å beregne hva mjølkeprodusenten må ha i merpris for mjølka for å opprettholde dekningsbidraget. Arbeidet er gjennomført som en litteraturstudie og som en egen analyse der vi brukte data fra fire økologiske mjølkeproduksjonsbruk i Rørosområdet, som leverer mjølk til Rørosmeieriet. For de fire bruka gjorde vi en scenarioanalyse der vi estimerte mjølkeproduksjon og fôrforbruk uten kraftfôr i beitetida, men med kraftfôr i innefôringstida, og helt uten kraftfôr i rasjonene. Data generert fra scenarioanalysen blei sammenlignet med dagens tilstand med hensyn på mjølkeytelse, næringsstoff-balanse og økonomi. Vi tok også ut mjølkeprøver fra tanken før beiteslipp og i beitetida for å analysere kvaliteten av mjølk.
Det er i norske forsøk funnet gjennomsnittlig mjølkeytelse på mellom 3000 og 5000 kg mjølk per ku og laktasjon uten kraftfôr. Scenarioanalysen viste at produksjonen helt uten kraftfôr er om lag 5500-6500 kg, mellom 22 og 26% lavere enn fôring opp mot produksjonspotensialet, og mellom 12 og 16% lavere dersom en gir kraftfôr i innefôringstida og ingen kraftfôr i beitetida. Totalt grovfôropptak vil være 19-27% høyere uten kraftfôr sammenlignet med fôring med kraftfôr. Litteraturanalysen viste at uten kraftfôr i rasjonen vil konsentrasjonen av fett og protein i mjølk reduseres, men andelen av ernæringsmessige gunstige fettsyrer (f.eks. C18:3n-3, og CLA) øker. Beiting har særlig positiv effekt på andelen av ernæringsmessige gunstige fettsyrer og reduserer samtidig de som regnes som ugunstige (f.eks. C14:0, C16:0). Videre så øker innholdet av E vitamin i mjølka på beite sammenlignet med innefôring. Analyse av tankmjølka fra de fire bruka viste stor variasjon i mjølkekvalitet, som sannsynligvis skyldes ulik fôring. Men det er tydelig effekt av beiting på fettsyresammensetning (redusert andel C16:0 og økt andel C18:3n-3). Det er tydelig at mjølkefettet produsert på beite var mykere enn mjølkefett fra innefôringsperioden.
Høstkalving og negativ energibalanse tidlig i laktasjonen kan gi dårlig fruktbarhet, og det er lettere å få til produksjon uten kraftfôr med konsentrert vårkavling. Lavere ytelse reduserer risikoen for enkelte produksjonssykdommer, men samtidig har bonden færre muligheter til å justere inntak av energi, protein og mineraler for å oppnå en balansert diett. Ketose kan bli en utfordring når kraftfôrandelen reduseres eller hvis kraftfôret kuttes helt ut. Moderat hold i sinperioden forebygger flere produksjons-relaterte sjukdommer. Det er svært viktig å følge opp med tilskudd av mineraler og vitaminer i rasjoner uten kraftfôr, siden dette ofte er tilsatt kraftfôret. Videre er det viktig å ha energirikt grovfôr i starten av laktasjonen, og en må ha økt fokus på grovfôrkvalitet og ta regelmessige grovfôranalyser.
Import av husdyrgjødsel er en viktig kilde for nitrogen (N), fosfor (P) og kalium (K), og bidrar til at på de fleste gårdene er det et lite overskudd av disse næringsstoffene i dag. Scenarionalysen viste at for alle gårdene ble næringsstoffbalansen av N, P og K lavere sammenlignet med dagens drift når kraftfôr helt eller delvis ble kuttet ut. For gårdene som ikke importerer husdyrgjødsel, blir næringsstoffbalansen så vidt positiv for N og omtrent i balanse for P og K. Dersom det ikke kjøpes inn noe kraftfôr, er det tendenser til negativ næringsstoffbalanse. Det blir viktig å følge utviklingen i næringsinnholdet i jorda hvis kraftfôrinnkjøpet reduseres eller kuttes ut.
Den økonomiske analysen viste at mjølkeleveransene blir redusert sammenlignet med dagnes drift når kraftfôr helt eller delvis blir kuttet ut. For tre av de fire bruka vil det gjøre at dekningsbidraget reduseres, mens det for det siste opprettholdes. For at dekningsbidraget skal opprettholdes på dagnes nivå, må merprisen på mjølk være 0 - 0,84 kr/liter der kraftfôr kuttes i beitetida, og 0 – 1,94 kr/liter dersom kraftfôr kuttes helt ut. Årsaken til den store variasjonen i behovet for merpris, skyldes i all hovedsak variasjon i arealgrunnlag. For bruk som har stort areal eller lav kraftfôrtildeling i dag kan en overgang til drift med lite eller ikke noe kraftfôr være mulig uten store økonomiske konsekvenser.
Vi konkluderer med at dersom det er ønske om mjølk med høy ernæringsmessig kvalitet, så vil det beste være å bare unngå kraftfôr i beitetida. Beiting uten tilskudd med kraftfôr er lettere å få til enn total kraftfôrfri fôring med hensyn til helse og fruktbarhet hos kyrne og økonomi, samtidig som mjølkekvaliteten på beite i stor grad vil være det samme om kua får kraftfôr i innefôringstida før beite eller ikke. Det er viktig å undersøke om en slik tilnærming er akseptabel for forbrukere som ønsker å kjøpe «grasfôra mjølk» til en merpris
Confirmation of the presence of a CRSF in the NICER spectrum of X 1822-371
Aims. X 1822-371 is an eclipsing binary system with a period close to 5.57 h and an orbital period derivative Porb of 1.42(3) × 10-10 s s-1. The extremely high value of its Porb is compatible with a super-Eddington mass transfer rate from the companion star and, consequently, an intrinsic luminosity at the Eddington limit. The source is also an X-ray pulsar, it shows a spin frequency of 1.69 Hz and is in a spin-up phase with a spin frequency derivative of 7.4 × 10-12 Hz s-1. Assuming a luminosity at the Eddington limit, a neutron star magnetic field strength of B=8 × 1010 G is estimated. However, a direct measure of B could be obtained observing a CRSF in the energy spectrum. Analysis of XMM-Newton data suggested the presence of a cyclotron line at 0.73 keV, with an estimated magnetic field strength of B=(8.8 ± 0.3)× 1010 G. Methods. Here we analyze the 0.3-50 keV broadband spectrum of X 1822-371 combining a 0.3-10 keV NICER spectrum and a 4.5-50 keV NuSTAR spectrum to investigate the presence of a cyclotron absorption line and the complex continuum emission spectrum. Results. The NICER spectrum confirms the presence of a cyclotron line at 0.66 keV. The continuum emission is modeled with a Comptonized component, a thermal component associated with the presence of an accretion disk truncated at the magnetospheric radius of 105 km and a reflection component from the disk blurred by relativistic effects. Conclusions. We confirm the presence of a cyclotron line at 0.66 keV inferring a NS magnetic field of B=(7.9 ± 0.5)× 1010 G and suggesting that the Comptonized component originates in the accretion columns
Spectral analysis of the AMXP IGR J17591-2342 during its 2018 outburst
The Accreting Millisecond X-ray Pulsar IGR J17591-2342 is a LMXB system that
went in outburst on August 2018 and it was monitored by the NICER observatory
and partially by other facilities. We aim to study how the spectral emission of
this source evolved during the outburst, by exploiting the whole X-ray data
repository of simultaneous observations. The continuum emission of the combined
broad-band spectra is on average well described by an absorbed Comptonisation
component scattering black-body-distributed photons peaking at (0.8+/-0.5) keV,
by a moderately optically thick corona (tau=2.3+/-0.5) with temperature of
(34+/-9) keV. A black-body component with temperature and radial size of
(0.8+/-0.2) keV and (3.3+/-1.5) km respectively is required by some of the
spectra and suggests that part of the central emission, possibly a fraction of
the neutron star surface, is not efficiently scattered by the corona. The
continuum at low energies is characterised by significant residuals suggesting
the presence of an absorption edge of O VIII and of emission lines of Ne IX
ions. Moreover, broad Fe I and Fe XXV K-alpha emission lines are detected at
different times of the outburst, suggesting the presence of reflection in the
system.Comment: 13 pages, 7 figures, accepted for publication on MNRA
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Expansion of Thaumarchaeota habitat range is correlated with horizontal transfer of ATPase operons.
Thaumarchaeota are responsible for a significant fraction of ammonia oxidation in the oceans and in soils that range from alkaline to acidic. However, the adaptive mechanisms underpinning their habitat expansion remain poorly understood. Here we show that expansion into acidic soils and the high pressures of the hadopelagic zone of the oceans is tightly linked to the acquisition of a variant of the energy-yielding ATPases via horizontal transfer. Whereas the ATPase genealogy of neutrophilic Thaumarchaeota is congruent with their organismal genealogy inferred from concatenated conserved proteins, a common clade of V-type ATPases unites phylogenetically distinct clades of acidophilic/acid-tolerant and piezophilic/piezotolerant species. A presumptive function of pumping cytoplasmic protons at low pH is consistent with the experimentally observed increased expression of the V-ATPase in an acid-tolerant thaumarchaeote at low pH. Consistently, heterologous expression of the thaumarchaeotal V-ATPase significantly increased the growth rate of E. coli at low pH. Its adaptive significance to growth in ocean trenches may relate to pressure-related changes in membrane structure in which this complex molecular machine must function. Together, our findings reveal that the habitat expansion of Thaumarchaeota is tightly correlated with extensive horizontal transfer of atp operons
H spectroscopy of the high-inclination black hole transient Swift J1357.2-0933 during quiescence
Swift J1357.2-0933 is a transient low-mass X-ray binary hosting a
stellar-mass black hole. The source exhibits optical dips and very broad
emission lines during both outburst and quiescence, which are thought to be the
result of a high orbital inclination. We present phase-resolved spectroscopy
obtained with the 10.4m Gran Telescopio Canarias (GTC). The spectra focus on
the spectral region during X-ray quiescence. The emission line is
exceptionally broad (full width at half maximum, FWHM > 4000 \AA), in agreement
with previous studies focused on . A two-Gaussian fit to the
prominent double-peaked profile reveals a periodic variability in the centroid
position of the line. We also produced a diagnostic diagram aimed at
constraining additional orbital parameters. Together, they allow us to
independently confirm the orbital period of the system using a new dataset
obtained five years after the previous outburst. However, our estimates for
both the systemic velocity and the radial velocity semi-amplitude of the black
hole reveal larger values than those found in previous studies. We argue that
this could be explained by the precession of the disc and the presence of a
hotspot. We found evidence of a narrow inner core in the double-peaked H
emission profile. We studied its evolution across the orbit, finding that it is
likely to result from the occultation of inner material by the outer rim bulge,
further supporting the high orbital inclination hypothesis.Comment: 6 pages, 4 figure
Soft-state optical spectroscopy of the black hole MAXI J1305-704
The X-ray dipper MAXI J1305-704 is a dynamically confirmed black hole (BH) X-ray binary discovered a decade ago. While its only outburst has been studied in detail in X-rays, follow-up at other wavelengths has been scarce. We report here the results from an optical spectroscopy campaign across the outburst of MAXI J1305-704. We analysed two epochs of data obtained by the Magellan Clay Telescope during two consecutive nights, when the source was in a soft X-ray spectral state. We identified typical emission lines from outbursting low-mass X-ray binaries, such as the hydrogen Balmer series, He II 4686 angstrom and the Bowen blend. We focused our analysis on the prominent H alpha line, which exhibits asymmetric emission and variable absorption components. We applied both traditional analytical methods and machine-learning techniques in order to explore the association of the absorption features with outflowing phenomena, and we conclude that they are best explained by broad absorption. This result is consistent with reports from other outbursting BHs, where optical outflows have predominantly been observed in the hard state. Further observations at different X-ray states are key to properly test whether this behaviour is universal and to determine the implications for the disc wind physics
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