Variation spatio-temporelle de l'activité d'alimentation des éléphants de mer en relation avec les paramètres physiques et biologiques de l'environnement

De nombreux travaux se sont intéressés à étudier l'activité d'alimentation des prédateurs marins en relation avec les conditions océanographiques. Cependant, l'activité alimentaire des ces prédateurs était souvent indirectement estimée à partir de l'analyse de leur trajectoire en mer, ainsi c'est plus le comportement de recherche alimentaire des prédateurs qui était étudié que leur prise alimentaire. Récemment, de nouvelles balises équipées d'accéléromètres ont été mise en œuvre afin d'évaluer les événements de prise alimentaire à fine échelle spatiale et temporelle. En combinant ces nouvelles technologies avec des enregistreurs permettant de collecter à haute fréquence des données sur l'environnement, cette thèse s'est donné pour objectif d'évaluer si le changement spatio-temporel de l'activité d'alimentation d'un prédateur marin, l'éléphant de mer du sud (SES) était relié à l'hétérogénéité des conditions physiques et biologiques rencontrées. Deux résultats principaux ont été mis en évidence. Dans un premier temps, en mettant en relation l'activité d'alimentation des SES avec trois paramètres physiques : la température, la lumière et la profondeur, cinq environnements d'alimentation distincts ont été caractérisé pour ce prédateur. Dans un deuxième temps, une relation qualitative a été montré entre la bioluminescence et l'activité d'alimentation des SES. Tout en apportant des résultats novateurs sur l'écologie des SES, cette thèse a développé des méthodes qui ont le potentiel d'être appliquées à un grand nombre de prédateurs plongeurs et qui ouvrent des perspectives de recherches importantes sur leur l'écologie et sur l'étude des relations prédateurs/proies.Numerous studies focused on the study of the foraging activity of marine predators in relation to oceanographic conditions. However, the foraging activity of marine predators was often indirectly estimated from the analysis of their trajectory at sea and consequently, it is more the searching behavior of predators which was studied than their food intake. Recently, new devices equipped with of accelerometers have been implemented to evaluate the events of food intake. By combining these technologies with devices recording high frequency data on the environment, this phD aims to assess whether the spatio-temporal variation of the foraging activity of a marine predator, the southern elephant seal (SES), is related to the heterogeneity of the physical and biological conditions encountered. Two main results were highlighted. Firstly, by linking the foraging activity of SES with three physical parameters, the temperature, the light and the depth, five distinct foraging environments were characterized for this predator. Secondly, a qualitative relationship was found between the bioluminescence and the foraging activity of SES. While providing innovative results on the ecology of SES, this phD developed methods that have the potential to be applied to a large number of marine predators and that provide research opportunities on the study of predator / prey interactions

On the relevance of APIs facing fairwashed audits

Recent legislation required AI platforms to provide APIs for regulators to assess their compliance with the law. Research has nevertheless shown that platforms can manipulate their API answers through fairwashing. Facing this threat for reliable auditing, this paper studies the benefits of the joint use of platform scraping and of APIs. In this setup, we elaborate on the use of scraping to detect manipulated answers: since fairwashing only manipulates API answers, exploiting scraps may reveal a manipulation. To abstract the wide range of specific API-scrap situations, we introduce a notion of proxy that captures the consistency an auditor might expect between both data sources. If the regulator has a good proxy of the consistency, then she can easily detect manipulation and even bypass the API to conduct her audit. On the other hand, without a good proxy, relying on the API is necessary, and the auditor cannot defend against fairwashing. We then simulate practical scenarios in which the auditor may mostly rely on the API to conveniently conduct the audit task, while maintaining her chances to detect a potential manipulation. To highlight the tension between the audit task and the API fairwashing detection task, we identify Pareto-optimal strategies in a practical audit scenario. We believe this research sets the stage for reliable audits in practical and manipulation-prone setups.Comment: 18 pages, 7 figure

Autumn movements of fin whales (Balaenoptera physalus) from Svalbard, Norway, revealed by satellite tracking

Insight into animal movements is essential for understanding habitat use by individuals as well as population processes and species life-history strategies. In this study, we instrumented 25 fin whales with ARGOS satellite-transmitters in Svalbard, Norway, to study their movement patterns and behaviour (Area Restricted Search (ARS), transiting or unknown) during boreal autumn/early winter. Ten of the whales stayed in the tagging area (most northerly location: 81.68°N) for their entire tracking periods (max 45 days). The other 15 whales moved in a south-westerly direction; the longest track ended off the coast of northern Africa (> 5000 km from the tagging location) after 96 days. The whales engaged in ARS behaviour intermittently throughout their southward migrations. During transit phases the whales moved quickly; one individual maintained an average horizontal speed of 9.3 km/h (travelling 223 km per day) for a period of a week. This study documents that: (1) some fin whales might remain at high latitudes during winter; (2) the whales that do migrate probably feed along the way; (3) they can maintain high transiting speed for long periods and; (4) one breeding area for this species is likely located in deep, warm water some 100 km west of Morocco.publishedVersio

The Grizzly, December 9, 2004

Wendell Berry Visits Ursinus • In Memory of Mrs.Margot Richter • UC Theater Production Goes on the Road • DSAC Updates • New Honor Code at UC? • Ursinus Students Bring the Holidays to Campus • Civil Rights Movement Class Opens Minds • History Behind the Holidays • Reading Day • SAAC Clothing Drive • Opinions: Should Procrastination be Diagnosed as a Psychological Disease?; Out with Final Exams! Students Prefer Writing Papers; Letter to the Editor • Stanton\u27s Jersey Officially Retiredhttps://digitalcommons.ursinus.edu/grizzlynews/1574/thumbnail.jp

PENGARUH VARIASI SUHU PERLAKUAN PANAS MENGGUNAKAN GAS HIDROGEN TERHADAP KARAKTERISTIK TERMISTOR NTC BERBASIS Fe2O3-MnO-ZnO

Telah dilakukan pembuatan termistor NTC berbasis Fe2O3-MnO-ZnO dengan perlakuan panas yang suhunya divariasikan antara 200oC, 300oC, 400oC dan 500oC menggunakan gas hidrogen (93%Ar+7%H2). Dimana kandungan yang ada pada mineral yarosit yaitu hematit (Fe2O3) yang menjadi bahan utama termistor NTC. Proses pembuatan tersebut dimulai dengan pencampuran serbuk Fe2O3 (lokal) yang sudah digerus dengan MnO dan ZnO sampai didapatkan pasta berbasis Fe2O3-MnO-ZnO. Kemudian dilakukan proses screen printing pada film tebal mentah. Film tebal tersebut disinter pada suhu sinter 1100°C selama 2 jam. Film tebal hasil sinter dilapisi perak untuk memberikan kontak ohmik sehingga dapat dilakukan pengukuran resistansi. Resistansi film tebal diukur pada suhu 30-150oC dengan beda suhu sebesar 5oC. Film tebal yang telah diukur resistansinya, diberi perlakuan panas dengan memanaskannya pada suhu yang bervariasi di dalam atmosfer gas hidrogen. Setelah diberi perlakuan panas dilakukan kembali pengukuran resistansi. Selanjutnya dilakukan karakterisasi struktur kristal dan struktur mikro dianalisis dengan XRD dan SEM. Struktur kristal yang terbentuk yaitu hematit dan spinel, namun bertambahnya suhu perlakuan panas membuat struktur kristal cenderung amorf dan perlakuan panas yang diberikan tidak mempengaruhi ukuran butir. Hasil karakterisasi sifat listrik menunjukkan resistansi listrik menurun seiring bertambahnya suhu perlakuan panas dari 2537,67MΩ menjadi 3,69MΩ. Termistor yang memenuhi persyaratan pasar (≥2000K) yaitu yang diberi perlakuan panas pada suhu 200oC-400oC. ; NTC thermistor have been fabricated based Fe2O3-MnO-ZnO the heat treatment temperature is varied between 200oC, 300oC, 400oC and 500oC using hydrogen gas (93% Ar + 7% H2). Where the existing content on yarosit mineral is hematite (Fe2O3) which is the main ingredient of NTC thermistors. The creation process begins with the mixing of powders Fe2O3 (local) that have been crushed with MnO and ZnO based paste to obtain Fe2O3-MnO-ZnO. Then do the process of screen printing on thicker films crude. The thick film sintered at 1100°C sinter temperature for 2 hours. Thick film sintered silver coated to provide an ohmic contact resistance measurement so that it can be done. Thick film resistance measured at 30-150oC with a temperature difference of 5°C. Thick film has been measured resistance, heat-treated by heating at various temperatures in the atmosphere of hydrogen gas. After the heat treatment is carried back by resistance measurement. Further characterization of crystal structure and microstructure were analyzed by XRD and SEM. The crystal structure is formed that is hematite and spinel, but increasing the heat treatment temperature makes the crystal structure tend to be amorphous and heat treatment provided does not affect the size of the grains. The characterization results show electrical properties of electric resistance decreases as the heat treatment temperature of 2537.67MΩ be 3.69MΩ. Thermistor that meets the requirements of the market (≥2000K) is heat-treated at a temperature of 200oC-400oC

The Grizzly, October 7, 2004

Ursinus Students Help in the Fight Against Cancer • New Sports Bar Opening Near Campus • Sigma Who? Students try to Bring National Fraternity to Campus • Did you Watch the Presidential Debates? • Spotlight on Alpha Sigma Nu • Ursinus Political Campaign • From Ursinus to the Publishing House: An Interview with Dr. Schroeder • Opinions: Political Campaign Ads: Too Negative or the Price we Pay for Living in a Democracy?; Why not the Guillotine?; Curbside Pickup: A Classier Alternative to Fast Food; Wismer Worries; Passing Time with Haikus • Ursinus Cross Country 2004 Kicks-off • Field Hockey Comes out Strong in 2004 Seasonhttps://digitalcommons.ursinus.edu/grizzlynews/1567/thumbnail.jp

The Grizzly, December 2, 2004

UC Students Opposed to Drunk Driving • Post-election Blues Give Rise to New Interest Group on Campus • Behind Closed Doors: Secret Places on Campus • Wheelchair Basketball Rolls in the Money • Upcoming Choir Concert • Interview with the President: Strassburger Shares Plans for Ursinus • Dance Company Concert a Success • Holly Singh Presents Mistaken Identity: Sikhs in America at Unity House • Major Highlight: Gender and Women\u27s Studies • Opinions: Enjoy Your Carbs this Holiday Season; Freedom on the Line • Pro Athletes Brawling with Fans • Men\u27s Basketball Season Heating Uphttps://digitalcommons.ursinus.edu/grizzlynews/1573/thumbnail.jp

Efectos psicológicos del cine de terror en los estudiantes de la generación Z de la Universidad de Ciencias y Artes de América Latina en el año 2021.

El trabajo analiza los diferentes efectos psicológicos que el espectador adquiere al ver contenidos cinematográficos de terror. Se hará uso de diferentes fuentes documentales, artículos académicos y una investigación cualitativa y cuantitativ

Changes in bone quality after switching from a TDF to a TAF based ART: A pilot randomized study

BackgroundThe impact of tenofovir disoproxil fumarate (TDF) antiretroviral (ART) regimens on bone health has been characterized mostly by bone mineral density (BMD), but recently also by bone quality (BQ). The aim of this pilot study is to assess the changes in BMD and BQ after switch from TDF to tenofovir alafenamide (TAF) ART.MethodsHIV individuals receiving TDF-based ART were randomized to switch to Bictegravir-TAF-Emtricitabine or to remain in the same regimen. At baseline and 24-weeks after randomization, participants underwent bone mineral density (BMD) by DXA and BQ assessment using bone microindentation, a validated technique that measures bone tissue quality expressed as bone material strength index (BMSi). A panel of plasma bone turnover biomarkers were measured by ELISA at the same time-points. Values are expressed as median [interquartile range] and non-parametric tests were used where appropriate.ResultsA total of 24 HIV individuals were included in the study, 19 of which were men (80%). Median age at baseline was 43 years (IQR 38-54). Half of individuals were allocated in the TDF group while the other half changed to TAF treatment. No differences at baseline between both groups were detected in any parameter. Non-significant changes nor in lumbar or femoral BMD at week 24 was found in any regimen. In contrast, there was an increase in BMSi in the TAF arm at 24 weeks, and thus an improvement in BQ[81.6 (79-83) to 86 (80-88) (+5.1%);p=0.041], whereas the TDF arm remained stable from 82 (76-85) at baseline to 82 (73-83);p=0.812. Hence, at week 24 there were significant differences in BQ between arms (p=0.049). A reduction in bone formation markers was found at week 24 in both regimens: N-terminal propeptide of type-1 collagen decreased a 20% (-35 - -0.6); p=0.031 with TAF and -16% (-25 - -5); p=0.032 with TDF. Also a decrease in bone resorption marker C-telopeptide with TAF was detected [-10% (-19 - -5);p=0.028] but not with TDF (p=0.232), suggesting a less metabolically active bone after switching to TAF.ConclusionA bone quality improvement was found after switching from a TDF to a TAF based ART independently of BMD, suggesting that the bone health benefits of TAF may extend beyond BMD. Future research should be directed to confirm these findings and to identify the underlying mechanisms of ART related bone toxicity