849,740 research outputs found
A record of fossil shallow-water whale falls from Italy
Twenty-five Neogene-Quaternary whales hosted in Italian museum collections and their associated fauna were analysed for evidence of whale-fall community development in shallow-water settings. The degree of bone articulation, completeness of the skeleton and lithology of the embedding sediments were used to gather information on relative water depth, water energy, sedimentation rate and overall environmental predictability around the bones. Shark teeth and hard-shelled invertebrates with a necrophagous diet in close association with the bones were used as evidence of scavenging. Fossil bone bioerosion, microbially mediated cementation and other mollusc shells in the proximity of the remains informed on past biological activity around the bones. The results are consistent with the hypothesis that shallow-water whale falls differ from their deep-water counterparts. Taphonomic pathways are more variable on the shelf and whale carcasses may not go through all steps of the ecological succession as recognised in the deep sea. Whilst the mobile scavenger and the enrichment opportunistic stages are well represented, chemosynthetic taxa typical of the sulphophilic stage were recovered only in one instance. The presence of a generalist fauna among the suspension feeding bivalves and carnivorous gastropods, and the extreme rarity of chemosynthetic taxa, suggest that predatory pressure rules out whale-fall specialists from shallow shelf settings as in analogous cold seep and vent shallow-water communities. © 2014 The Lethaia Foundation
U and Th content in the Central Apennines continental crust: a contribution to the determination of the geo-neutrinos flux at LNGS
The regional contribution to the geo-neutrino signal at Gran Sasso National
Laboratory (LNGS) was determined based on a detailed geological, geochemical
and geophysical study of the region. U and Th abundances of more than 50
samples representative of the main lithotypes belonging to the Mesozoic and
Cenozoic sedimentary cover were analyzed. Sedimentary rocks were grouped into
four main "Reservoirs" based on similar paleogeographic conditions and
mineralogy. Basement rocks do not outcrop in the area. Thus U and Th in the
Upper and Lower Crust of Valsugana and Ivrea-Verbano areas were analyzed. Based
on geological and geophysical properties, relative abundances of the various
reservoirs were calculated and used to obtain the weighted U and Th abundances
for each of the three geological layers (Sedimentary Cover, Upper and Lower
Crust). Using the available seismic profile as well as the stratigraphic
records from a number of exploration wells, a 3D modelling was developed over
an area of 2^{\circ}x2^{\circ} down to the Moho depth, for a total volume of
about 1.2x10^6 km^3. This model allowed us to determine the volume of the
various geological layers and eventually integrate the Th and U contents of the
whole crust beneath LNGS. On this base the local contribution to the
geo-neutrino flux (S) was calculated and added to the contribution given by the
rest of the world, yielding a Refined Reference Model prediction for the
geo-neutrino signal in the Borexino detector at LNGS: S(U) = (28.7 \pm 3.9) TNU
and S(Th) = (7.5 \pm 1.0) TNU. An excess over the total flux of about 4 TNU was
previously obtained by Mantovani et al. (2004) who calculated, based on general
worldwide assumptions, a signal of 40.5 TNU. The considerable thickness of the
sedimentary rocks, almost predominantly represented by U- and Th- poor
carbonatic rocks in the area near LNGS, is responsible for this difference.Comment: 45 pages, 5 figures, 12 tables; accepted for publication in GC
Epidemiology and Outcomes of Vertebral Artery Injury in 16 582 Cervical Spine Surgery Patients: An AOSpine North America Multicenter Study.
STUDY DESIGN: A multicenter retrospective case series was compiled involving 21 medical institutions. Inclusion criteria included patients who underwent cervical spine surgery between 2005 and 2011 and who sustained a vertebral artery injury (VAI).
OBJECTIVE: To report the frequency, risk factors, outcomes, and management goals of VAI in patients who have undergone cervical spine surgery.
METHODS: Patients were evaluated on the basis of condition-specific functional status using the Neck Disability Index (NDI), modified Japanese Orthopaedic Association (mJOA) score, the Nurick scale, and the 36-Item Short-Form Health Survey (SF-36).
RESULTS: VAIs were identified in a total of 14 of 16 582 patients screened (8.4 per 10 000). The mean age of patients with VAI was 59 years (±10) with a female predominance (78.6%). Patient diagnoses included myelopathy, radiculopathy, cervical instability, and metastatic disease. VAI was associated with substantial blood loss (770 mL), although only 3 cases required transfusion. Of the 14 cases, 7 occurred with an anterior-only approach, 3 cases with posterior-only approach, and 4 during circumferential approach. Fifty percent of cases of VAI with available preoperative imaging revealed anomalous vessel anatomy during postoperative review. Average length of hospital stay was 10 days (±8). Notably, 13 of the 14 (92.86%) cases resolved without residual deficits. Compared to preoperative baseline NDI, Nurick, mJOA, and SF-36 scores for these patients, there were no observed changes after surgery (P = .20-.94).
CONCLUSIONS: Vertebral artery injuries are potentially catastrophic complications that can be sustained from anterior or posterior cervical spine approaches. The data from this study suggest that with proper steps to ensure hemostasis, patients recover function at a high rate and do not exhibit residual deficits
Changes of benthic macroinvertebrates in Thi Vai River and Cai Mep Estuaries under polluted conditions with industrial wastewater
The pollution on the Thi Vai River has been spreading out rapidly over the two lasted decades caused by the wastewater from the industrial parks in the left bank of Thi Vai River and Cai Mep Estuaries. The evaluation of the benthic macroinvertebrate changes was very necessary to identify the consequences of the industrial wastewater on water quality and aquatic ecosystem of Thi Vai River and Cai Mep Estuaries.
In this study, the variables of benthic macroinvertebrates and water quality were investigated in Thi Vai River and Cai Mep Estuaries, Southern Vietnam. The monitoring data of benthic macroinvertebrates and water quality parameters covered the period from 1989 to 2015 at 6 sampling sites in Thi Vai River and Cai Mep Estuaries. The basic water quality parameters were also tested including pH, dissolved oxygen (DO), total nitrogen, and total phosphorus. The biodiversity indices of benthic macroinvertebrates were applied for water quality assessment.
The results showed that pH ranged from 6.4 – 7.6 during the monitoring. The DO concentrations were in between 0.20 – 6.70 mg/L. The concentrations of total nitrogen and total phosphorous ranged from 0.03 – 5.70 mg/L 0.024 – 1.380 mg/L respectively. Macroinvertebrate community in the study area consisted of 36 species of polychaeta, gastropoda, bivalvia, and crustacea, of which, species of polychaeta were dominant in species number. The benthic macroinvertebartes density ranged from 0 – 2.746 individuals/m2 with the main dominant species of Neanthes caudata, Prionospio malmgreni, Paraprionospio pinnata, Trichochaeta carica, Maldane sarsi, Capitella capitata, Terebellides stroemi, Euditylia polymorpha, Grandidierella lignorum, Apseudes vietnamensis. The biodiversity index values during the monitoring characterized for aquatic environmental conditions of mesotrophic to polytrophic. Besides, species richness positively correlated with DO, total nitrogen, and total phosphorus. The results confirmed the advantage of using benthic macroinvertebrates and their indices for water quality assessment
COMMUNICATION AND COORDINATION IN THE LABORATORY COLLECTIVE RESISTANCE GAME
This paper presents a laboratory collective resistance (CR) game to study how different forms of non-binding communication among responders can help coordinate their collective resistance against a leader who transgresses against them. Contrary to the predictions of analysis based on purely self-regarding preferences, we find that non-binding communication about intended resistance increases the incidence of no transgression even in the one-shot laboratory CR game. In particular, we find that the incidence of no transgression increases from 7 percent with no communication up to 25-37 percent depending on whether communication occurs before or after the leader’s transgression decision. Responders’ messages are different when the leaders can observe them, and the leaders use the observed messages to target specific responders for transgression.Communication, Cheap Talk, Collective Resistance, Laboratory Experiment, Social Preferences
COORDINATING COLLECTIVE RESISTANCE THROUGH COMMUNICATION AND REPEATED INTERACTION
This paper presents a laboratory collective resistance (CR) game to study how different forms of repeated interactions, with and without communication, can help coordinate subordinates' collective resistance to a ???divide-and-conquer??? transgression against their personal interests. In the one-shot CR game, a first???mover (the ???leader???) decides whether to transgress against two responders. Successful transgression increases the payoff of the leader at the expense of the victim(s) of transgression. The two responders then simultaneously decide whether to challenge the leader. The subordinates face a coordination problem in that their challenge against the leader's transgression will only succeed if both of them incur the cost to do so. The outcome without transgression can occur in equilibrium with standard money-maximizing preferences with repeated interactions, but this outcome is not an equilibrium with standard preferences when adding non-binding subordinate ???cheap talk??? communication in the one-shot game. Nevertheless, we find that communication (in the one-shot game) is at least as effective as repetition (with no communication) in reducing the transgression rate. Moreover, communication is better than repetition in coordinating resistance, because it makes it easier for subordinates to identify others who have social preferences and are willing to incur the cost to punish a violation of social norms.Communication, Cheap Talk, Collective Resistance, Divide-and-Conquer, Laboratory Experiment, Repeated Games, Social Preferences
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