bluuebunny/crossref_metadata_2025 huggingface dataset:
PROFESSIONAL IDENTITY AND EMPLOYMENT OF YOUNG GRADUATES (ALEVEL + 4 YEARS, A-LEVEL + 5 YEARS) IN ABIDJAN
Authors: SALI YEO KONE Dr. LOKOTIANWA
Published: July 2022

While education is the path par excellence to success, young graduates have inflated the already alarming rate of unemployment in recent years. The employment of young graduates and those of higher education in particular, is one of the problems encountered by many countries, particularly Côte d'Ivoire. To this end, it is important that particular attention be paid to it in order to lead to an understanding of the phenomenon and to propose reflections as to solutions. This study therefore aims to examine the relationship between professional identity and the integration of young higher education graduates in Abidjan. In other words, the objective of this work is to analyze the problem of the integration of young higher education graduates and to try to explain it in the light of the aforementioned variable, namely professional identity. It concerns two hundred and twenty (220) young graduates of higher education (A-level + 4 years; A-level + 5 years) whose age varies between 18 and 35 years. The approach consisted of collecting information from these young people about their professional identity through a questionnaire. This information allowed us to categorize the subjects according to whether they present a successful or confused professional identity and relate it to professional integration. The statistical processing of the data gives a very significant Chi-square (X² = 12.04; P ≤ 0.001) and shows the existence of a link between the two variables under study. Thus, the analyzes reveal that young graduates with a successful professional identity are more likely to integrate compared to their peers who have a confused professional identity. These results confirm the working hypothesis put forward at the start and are in line with those of previous work carried out in this field. They allow an understanding of the phenomenon of unemployed graduates with regard to the Social Cognitive Theory of Careers of Lent Brown and Hackett (1994) and constitute an important contribution for researchers in education.
EXPLORING HOW SCIENCE TEACHERS USE MANIPULATIVE TEACHING MATERIALS IN THE CLASSROOM: A CASE OF SCHOOLS IN MANZINI REGION
Authors: MASEKO THAMSANQA , BHEBHE SITHULISIWE , THABISO MAFU
Published: July 2022

This study sought to explore how science teachers use manipulative teaching material in the classroom. The study was based on the following objectives: establish the benefits of using manipulative teaching materials, determine the challenges faced by science teachers towards using manipulative teaching materials and suggest how science teachers may overcome the challenges faced in using manipulative teaching materials. Underpinned by the constructivism learning theory, a qualitative research approach was adopted where a case study research design was employed with a purposely selected sample of twelve (12) primary school science teachers who were randomly selected from four schools. Data were analyzed using thematic analysis. The findings of the study revealed that there are benefits of using manipulative teaching materials. These were that, learners make sense of the theory and have a clear understanding of the concepts taught, learners also acquired scientific skills and manipulative teaching materials motivate learners to participate in the lesson, therefore this makes it hard for learners to lose attention. The study also revealed the challenges faced by teachers in using manipulative teaching materials were lack of resources needed in the science lessons, failure to meet the demands of the subject, and the number of learners in the classroom. The study further revealed that all these challenges could be minimized by the government building science laboratories in the schools and that teachers should improvise the manipulative teaching materials. Based on the findings, the study concludes that manipulative teaching materials play an important role in the teaching and learning of science.
SELECTION OF ISOLATES OF LOCAL ENDOPHYTIC BACTERIA CELLULOLYTIC STRAINS FROM MANGROVE ROOTS Ceriops tagal (Perr) C. B. Rob
Authors: Devy Silvera
Published: July 2022

Cellulose agricultural waste is a source of environmental pollution and an alternative solution to overcome it is to degrade this waste with the help of cellulolytic enzymes. The Biochemistry Laboratory of FMIPA Riau University has a number of endophytic bacterial isolates from the roots of Mangrove Ceriops tagal (Perr) C. B. Rob in the Bengkalis area whose potential to produce cellulolytic enzymes is not yet known. Qualitative selection in carboxy methyl cellulose (CMC) solid media from 24 isolates of endophytic bacteria that were able to live because they produced cellulolytic enzymes, only 22 isolates. Quantitatively using the DNS (Dinitro Salicylic Acid) method, 3 of these 22 isolates had relatively higher activity than other isolates. The activity of isolate C-9 (LBKURCC332) was 572x10-4±0.0069U/mL, isolate C-23(LBKURCC346) was 423x10-4±0.0027U/mL and isolate C-30 (LBKURCC353) was 384x10-4± 0.0003 U/mL and statistically these 3 cellulolytic activities were significantly different
Структура скрученої групової алгебри для алгебри, отриманої за допомогою процесу Келі – Діксона
Authors: Boboescu R. , Flaut C.
Published: July 2022

УДК 512.55Дотримуючись iдей Бейлiса [J. W. Bales,  A tree for computing the Cayley-Dickson twist, Missouri J. Math. Sci., 21, No. 2, 83-93 (2009)], у цiй статтi запропоновано алгоритм обчислення елементiв базису алгебри, отриманої за допомогою процесу Келi – Дiксона. Як наслiдок доведено, що алгебра, отримана за допомогою процесу Келi – Дiксона, є скрученою груповою алгеброю для групи

G
=

ℤ
2
n

,
n
=

2
t

,

t
∈
ℕ

над полем

K

з 

K
≠
2

. Наведено властивостi i деякi застосування неасоцiативних алгебр кватернiонiв.
Найкращі ортогональні тригонометричні наближення класів типу Нікольського – Бєсова періодичних функцій у просторі

B

∞
,1
Authors: Hembars’ka S. B. , Zaderei P. V.
Published: July 2022

УДК 517.51
Одержано точні за порядком оцінки найкращих ортогональних тригонометричних наближень класів   типу Нікольського – Бєсова періодичних функцій однієї та багатьох змінних у просторі 

B

∞
,1

.
Reabilitação da pessoa com amputação major de etiologia vascular: estudo exploratório
Authors: Santos Isabel , Sousa Pedro
Published: July 2022

Enquadramento: a reabilitação precoce é essencial na recuperação da pessoa com amputação major de etiologia vascular, mas o seu processo de reabilitação pós-operatório não está suficientemente estudado. Objetivo: caraterizar o processo de reabilitação pós-amputação major do membro inferior, por etiologia vascular. Metodologia: estudo exploratório e retrospetivo, com 40 pessoas com amputação major de etiologia vascular num hospital central português, entre 1 a 36 meses de pós-operatório. Foi aplicado um questionário para avaliar dados sociodemográficos, clínicos, reabilitação, adaptação ao domicílio, protetização e independência funcional. Os dados foram analisados através de estatística descritiva e inferencial. Resultados: constatou-se que 92,5% realizaram reabilitação pós-operatória, 65% regressaram ao domicílio e 72,5% realizaram alterações no domicílio. A taxa de protetização foi de 15%, com uma média de espera de 16,33 meses (DP=9,50). Na alta, o Índice de Barthel foi de 42,88, aumentando gradualmente no pós-operatório ([1-5 meses]: M=62,50; [6-11 meses]: M=77,35; [12-23 meses]: M=78,75). Conclusão: a maioria realizou reabilitação e houve uma evolução positiva da independência funcional. As principais dificuldades sentidas e as alterações realizadas no domicílio prendem-se com os autocuidados de higiene, transferências e uso do sanitário. Evidenciou-se a importância do envolvimento da família no processo de reabilitação e na preparação do regresso a casa.
Students’ knowledge regarding cervical posture when using a smartphone
Authors: Lopes Sofia , Silva Bruna , Araújo Fábio
Published: July 2022

Background:

in today’s world, we are facing a society dependent on smartphones. The repeated movements and the bad posture alongside its excessive usage promote musculoskeletal malfunctions. Objective: evaluate the individual’s knowledge about the cervical posture when using the smartphone, understand if there is any association between posture and the discomfort felt and, understand what is the self-awareness of the individuals regarding the posture they use. Methods: analytical study conceived among 318 students of the CESPU, and it was applied a questionnaire to characterize. Data it was analysed through with a significance level of 0.05. Results: 52 individuals have knowledge about the best cervical posture to adopt, and they indeed adopt it. It was an association between having knowledge and adopting good cervical posture and having less discomfort. This association was kept in the protective sense, and statistically significant when adjusted for age, BMI and schooling (OR=0.47). Among the group of students who knew the correct posture, having the first smartphone between the ages of 8 and 10 was a risk factor (OR=3.77), and using the smartphone less than 3 hours was a protective factor (OR=0.44). Conclusions:participants with the knowledge about good posture and indeed adopt it while using their smartphones, reveal a less discomfort. This association remained regardless the age, BMI and schooling of the participants. Having the first smartphone between the ages of 8 and 10 is a risk factor for not adopting a good cervical posture, and using the smartphone less than 3 hours a protective factor.
Resistencia inducida contra las enfermedades
Authors: Cristancho Ardila Marco Aurelio
Published: July 2022

La resistencia inducida tiene como base la activación de los mecanismos de defensa natural de las plantas antes de la llegada del patógeno. Esta inducción de resistencia se lleva a cabo con agentes bióticos y abióticos, con microorganismos y con agentes químicos sintéticos. En café se han desarrollado varios trabajos utilizando diversos microorganismos no patógenos o patógenos atenuados para tratar de inducir resistencia contra la roya /Hemileia vastatrix/. Dentro de los tratamientos que se han ensayado con este propósito están las formulaciones comerciales con /Bacillus thuringiensis/, aislamientos de la bacteria /Pseudomonas/ spp., urenidiosporas de /H. vastatrix/ inactivadas térmicamente y extractos crudos de células de la bacteria /Xanthomonas campestris/.
Control químico de enfermedades
Authors: Gil Vallejo Luis Fernando
Published: July 2022

Para contrarrestar el impacto de las enfermedades en los cultivos es posible utilizar prácticas de manejo, biocontroladores, resistencia genética y productos químicos. Por su habilidad para reducir el daño económico a niveles aceptables, el método más común para controlar enfermedades es el uso de compuestos químicos que inhiben la germinación, crecimiento y multiplicación de los patógenos, o son letales a ellos. En este capítulo se hace presenta la clasificación de los fungicidas, épocas y formas de aplicación y las medidas de precaución al aplicarlos.
Las Micorrizas arbusculares en el cultivo del café
Authors: Rivillas Osorio Carlos Alberto
Published: July 2022

En este capítulo se resalta la importancia que las micorrizas arbusculares tienen en las plantas, especialmente para la asociación con el café, en la etapa de germinación y de almácigo y en los cultivos de plátano y banano, por tratarse de cultivos de tradición de la zona cafetera colombiana.
Fastiginia, diario de un hombre ocioso
Authors: VILLA IÑIGO VALPUESTA
Published: July 2022

El funcionario portugués Tome Pinheiro da Veiga, durante su estancia en la ciudad de Valladolid en 1605 para resolución de ciertos asuntos burocráticos, escribiría el diario Fastiginia. Esta obra, de gran singularidad, tradicionalmente ha sido usada para documentar y estudiar la Valladolid de principios del Siglo XVII y la Corte de Felipe III; sin embargo, es un escrito de mucho interés desde otros puntos de vista, como por ejemplo el de la visualización del ocio. En su estancia en Valladolid, Pinheiro se dedicaría a describir, opinar y comparar los múltiples entretenimientos que la ciudad le ofrecía, convirtiendo su diario en una original experiencia y testimonio de la forma de entretenimiento dentro del ámbito urbano y en una excelente forma de acercarse al día a día de un hombre ocioso del pasado.
Hydrodynamics of Collisions and Close Encounters between Stellar Black Holes and Main-sequence Stars
Authors: Kremer Kyle , Lombardi James C. , Lu Wenbin , Piro Anthony L. , Rasio Frederic A.
Published: July 2022

Recent analyses have shown that close encounters between stars and stellar black holes occur frequently in dense star clusters. Depending upon the distance at closest approach, these interactions can lead to dissipating encounters such as tidal captures and disruptions, or direct physical collisions, all of which may be accompanied by bright electromagnetic transients. In this study, we perform a wide range of hydrodynamic simulations of close encounters between black holes and main-sequence stars that collectively cover the parameter space of interest, and we identify and classify the various possible outcomes. In the case of nearly head-on collisions, the star is completely disrupted with roughly half of the stellar material becoming bound to the black hole. For more distant encounters near the classical tidal-disruption radius, the star is only partially disrupted on the first pericenter passage. Depending upon the interaction details, the partially disrupted stellar remnant may be tidally captured by the black hole or become unbound (in some cases, receiving a sufficiently large impulsive kick from asymmetric mass loss to be ejected from its host cluster). In the former case, the star will undergo additional pericenter passages before ultimately being disrupted fully. Based on the properties of the material bound to the black hole at the end of our simulations (in particular, the total bound mass and angular momentum), we comment upon the expected accretion process and associated electromagnetic signatures that are likely to result.
The Astrophysical Distance Scale. V. A 2% Distance to the Local Group Spiral M33 via the JAGB Method, Tip of the Red Giant Branch, and Leavitt Law
Authors: Lee Abigail J. , Rousseau-Nepton Laurie , Freedman Wendy L. , Madore Barry F. , Cioni Maria-Rosa L. , Hoyt Taylor J. , Jang In Sung , Javadi Atefeh , Owens Kayla A.
Published: July 2022

The J-region asymptotic giant branch (JAGB) method is a new standard candle that is based on the stable intrinsic J-band magnitude of color-selected carbon stars, and has a precision comparable to other primary distance indicators such as Cepheids and the TRGB. We further test the accuracy of the JAGB method in the Local Group galaxy M33. M33's moderate inclination, low metallicity, and nearby proximity make it an ideal laboratory for tests of systematics in local distance indicators. Using high-precision optical BVI and near-infrared JHK photometry, we explore the application of three independent distance indicators: the JAGB method, the Cepheid Leavitt law, and the TRGB. We find: μ
0(TRGB
I
) = 24.72 ± 0.02 (stat) ± 0.07 (sys) mag, μ
0(TRGBNIR) = 24.72 ± 0.04 (stat) ± 0.10 (sys) mag, μ
0(JAGB) = 24.67 ± 0.03 (stat) ± 0.04 (sys) mag, and μ
0(Cepheid) = 24.71 ± 0.04 (stat) ± 0.01 (sys) mag. For the first time, we also directly compare a JAGB distance using ground-based and space-based photometry. We measure μ
0(JAGBF110W) = 24.71 ± 0.06 (stat) ± 0.05 (sys) mag using the (F814W−F110W) color combination to effectively isolate the JAGB stars. In this paper, we measure a distance to M33 accurate to 2% and provide further evidence that the JAGB method is a powerful extragalactic distance indicator that can effectively probe a local measurement of the Hubble constant using spaced-based observations. We expect to measure the Hubble constant via the JAGB method in the near future, using observations from the James Webb Space Telescope.
A Double-decker Filament Formation Driven by Sunspot Rotation and Magnetic Reconnection
Authors: Zhang Yan , Yan Xiaoli , Wang Jincheng , Li Qiaoling , Yang Liheng , Xue Zhike
Published: July 2022

In this paper, through analyzing data from the Solar Dynamics Observatory (SDO) and the Global Oscillation Network Group (GONG), we present a study on the formation of a double-decker filament in NOAA Active Region 12665 from 2017 July 8 to 14. We find that magnetic reconnection occurs between two smaller filaments to form a longer filament. According to the evolution of the leading sunspot, it is obvious that the sunspot experiences a continuous rotation around its umbra. During the period from 03:00 UT on July 11 to 10:00 UT on July 14, the average speed of sunspot rotation is about 3.°7 hr–1. The continuous rotation of sunspot stretches the filament and results in the formation of a reversed S-shaped filament. Due to the motion of the magnetic field and internal magnetic reconnection, the filament splits into two branches and forms a double-decker filament structure. In the process of filament separation, internal magnetic reconnection can also accelerate the filament separation. Nonlinear force-free field extrapolation indicates that there are two magnetic flux ropes, which are consistent with the observed results. Eventually, the upper filament erupts and produces an M-class flare and a halo coronal mass ejection.
Generation of Solar-like Differential Rotation
Authors: Hotta H. , Kusano K. , Shimada R.
Published: July 2022

We analyze the simulation result shown in Hotta & Kusano (2021) in which the solar-like differential rotation is reproduced. The Sun is rotating differentially with the fast equator and the slow pole. It is widely thought that the thermal convection maintains the differential rotation, but recent high-resolution simulations tend to fail to reproduce the fast equator. This fact is an aspect of one of the biggest problems in solar physics called the convective conundrum. Hotta & Kusano succeed in reproducing the solar-like differential rotation without using any manipulation with an unprecedentedly high-resolution simulation. In this study, we analyze the simulation data to understand the maintenance mechanism of the fast equator. Our analyses lead to conclusions that are summarized as follows. (1) The superequipatition magnetic field is generated by the compression, which can indirectly convert the massive internal energy to magnetic energy. (2) The efficient small-scale energy transport suppresses large-scale convection energy. (3) Non-Taylor–Proudman differential rotation is maintained by the entropy gradient caused by the anisotropic latitudinal energy transport enhanced by the magnetic field. (4) The fast equator is maintained by the meridional flow mainly caused by the Maxwell stress. The Maxwell stress itself also has a role in the angular momentum transport for the fast near-surface equator (we call it the P
unching ball effect). The fast equator in the simulation is reproduced not due to the low Rossby number regime but due to the strong magnetic field. This study newly finds the role of the magnetic field in the maintenance of differential rotation.
On the Dwarf Irregular Galaxy NGC 6822. I. Young, Intermediate, and Old Stellar Populations
Authors: Tantalo Maria , Dall’Ora Massimo , Bono Giuseppe , Stetson Peter B. , Fabrizio Michele , Ferraro Ivan , Nonino Mario , Braga Vittorio F. , da Silva Ronaldo , Fiorentino Giuliana , Iannicola Giacinto , Marengo Massimo , Monelli Matteo , Mullen Joseph P. , Pietrinferni Adriano , Salaris Maurizio
Published: July 2022

We present accurate and deep multiband (g, r, i) photometry of the Local Group dwarf irregular galaxy NGC 6822. The images were collected with wide-field cameras at 2 m/4 m (INT, CTIO, CFHT) and 8 m class telescopes (Subaru) covering a 2 deg2 field of view across the center of the galaxy. We performed point-spread function photometry of ≈7000 CCD images, and the final catalog includes more than 1 million objects. We developed a new approach to identify candidate field and galaxy stars and performed a new estimate of the galaxy center by using old stellar tracers, finding that it differs by 1.′15 (R.A.) and 1.′53 (decl.) from previous estimates. We also found that young (main sequence, red supergiants), intermediate (red clump, asymptotic giant branch (AGB)), and old (red giant branch) stars display different radial distributions. The old stellar population is spherically distributed and extends to radial distances larger than previously estimated (∼1°). The young population shows a well-defined bar and a disk-like distribution, as suggested by radio measurements, that is off-center compared with the old population. We discuss pros and cons of the different diagnostics adopted to identify AGB stars and develop new ones based on optical–near-IR–mid-IR color–color diagrams to characterize oxygen- and carbon-rich stars. We found a mean population ratio between carbon and M-type (C/M) stars of 0.67 ± 0.08 (optical/near-IR/mid-IR), and we used the observed C/M ratio with empirical C/M–metallicity relations to estimate a mean iron abundance of [Fe/H] ∼ −1.25 (σ = 0.04 dex), which agrees quite well with literature estimates.
The TeV Diffuse Cosmic Neutrino Spectrum and the Nature of Astrophysical Neutrino Sources
Authors: Fang Ke , Gallagher John S. , Halzen Francis
Published: July 2022

The diffuse flux of cosmic neutrinos has been measured by the IceCube Observatory from TeV to PeV energies. We show that an improved characterization of this flux at lower energies, TeV and sub-TeV, reveals important information on the nature of the astrophysical neutrino sources in a model-independent way. Most significantly, it could confirm the present indications that neutrinos originate in cosmic environments that are optically thick to GeV–TeV γ-rays. This conclusion will become inevitable if an uninterrupted or even steeper neutrino power law is observed in the TeV region. In such γ-ray-obscured sources, the γ-rays that inevitably accompany cosmic neutrinos will cascade down to MeV–GeV energies. The requirement that the cascaded γ-ray flux accompanying cosmic neutrinos should not exceed the observed diffuse γ-ray background puts constraints on the peak energy and density of the radiation fields in the sources. Our calculations inspired by the existing data suggest that a fraction of the observed diffuse MeV–GeV γ-ray background may be contributed by neutrino sources with intense radiation fields that obscure the high-energy γ-ray emission accompanying the neutrinos.
The Splashback Mass Function in the Presence of Massive Neutrinos
Authors: Ryu Suho , Lee Jounghun
Published: July 2022

We present a complementary methodology to constrain the total neutrino mass, ∑m

ν
, based on the diffusion coefficient of the splashback mass function of dark matter halos. Analyzing the snapshot data from the Massive Neutrino Simulations, we numerically obtain the number densities of distinct halos identified via the SPARTA code as a function of their splashback masses at various redshifts for two different cases of ∑m

ν
= 0.0 and 0.1 eV. Then, we fit the numerical results to the recently developed analytic formula characterized by the diffusion coefficient that quantifies the degree of ambiguity in the identification of the splashback boundaries. Our analysis confirms that the analytic formula works excellently even in the presence of neutrinos and that the decrement of its diffusion coefficient with redshift is well described by a linear fit, B(z − z

c
), in the redshift range of 0.2 ≤ z ≤ 2. It turns out that the massive neutrino case yields a significantly lower value of B and a substantially higher value of z

c
than the massless neutrino case, which indicates that the higher the masses that neutrinos have, the more severely the splashback boundaries become disturbed by the surroundings. Given our result, we conclude that the total neutrino mass can in principle be constrained by measuring how rapidly the diffusion coefficient of the splashback mass function diminishes with redshifts at z ≥ 0.2. We also discuss the anomalous behavior of the diffusion coefficient found at lower redshifts for both of the ∑m

ν
cases, and ascribe it to the fundamental limitation of the SPARTA code at z ≤ 0.13.
HbA1c as Early Warning Complications of Kidney Failure in Type 2 Diabetes Mellitus
Authors: Momot Simon L. , Agustarika Butet , Mustamu Alva Cherry , Sari Nurul Kartika
Published: July 2022

BACKGROUND: Chronic kidney disease is closely related to diabetes. Basic information about the treatment and physical condition of diabetic patients should be analyzed to provide further evidence of prevention. Based on the high prevalence of diabetes mellitus (DM) among patients with renal failure, there is a great need to learn more about its prevention and management including laboratory diagnostic tests because HbA1c levels are directly proportional to blood glucose levels.

AIM: The purpose of this study was to determine the effect of HbA1c levels on creatinine levels in patients with Type 2 DM.

METHODS: This type of research is a quantitative study with a cross-sectional approach. The sample in this study was 38 DM patients who had their diagnosis confirmed using consecutive sampling techniques. According to the healthcare centre’s data, the respondent’s blood sample was taken at the respondent’s house, and the HbA1c and creatinine levels were tested in the laboratory. Data analysis using the Chi-square test.

RESULTS: The results of this study indicate that there is no relationship between HbA1c levels and the incidence of kidney failure with p = 0.588, OR 0.658.

CONCLUSION: This research showed that there was no relationship between HbA1c levels with the incidence of kidney failure.
History and significance of tropical cave biology
Authors: Howarth Francis
Published: July 2022

“Nothing could possibly live there!” They said. Indeed, until recently, few specialized cave-adapted animals were known from volcanic, tropical, or oceanic island caves, and plausible theories had been put forward to explain their absence. But assume nothing in science! One must illuminate, explore, and survey habitats before declaring them barren. Our understanding of cave biology changed dramatically about 50 years ago following the serendipitous discovery of cave-adapted insects and other terrestrial arthropods in lava caves on the young oceanic islands of the Galapagos and Hawai‘i. The discovery and subsequent studies on the evolutionary ecology of cave animals have revealed a remarkable hidden fauna and created new sub-disciplines within biospeleology. Biological surveys of caves in other regions have confirmed the results developed in Hawai‘i. We now predict that, rather than being relicts trapped in caves by changing climate, animals actively colonized caves and adapted to exploit food resources wherever there were suitable subterranean voids. The physical environment in caves can be determined with great precision because the habitat is buffered by rock. Furthermore, the bizarre adaptations displayed by obligate cave animals are similar across many taxonomic groups. These two characteristics make caves nearly ideal natural laboratories for studying evolution and ecology. However, to the untrained researcher, caves can appear hostile and dangerous, and in fact, fieldwork in caves requires a unique marriage of athletic ability and science. In other words, it is exciting! Join me on a virtual tour of exploration, discovery, and research in caves during the past half-century.
The fascinating biology of stinky caves
Authors: Sarbu Serban
Published: July 2022

The discovery of Movile Cave in 1986, similarly to the discovery of the deep-sea vents 9 years earlier, showed that, when redox interfaces are present in subsurface ecosystems, diverse and abundant biological communities can thrive based primarily on autochthonous food produced in situ by chemosynthesis. Additional caves, partially flooded by sulfidic water have been discovered, i.e. the Frasassi caves in Italy, Ein-Nur Cave and Ayyalon Cave in Israel, Melissotrypa Cave in Greece, Tashan Cave in Iran, caves in the Sharo-Argun Valley in the Caucasus Mountains, etc. All of these are inhabited by numerous endemic cave-adapted organisms present in dense populations sustained by a rich food base generated within the subterranean environment by microorganisms that use atmospheric oxygen to oxidize the reduced chemical compounds present in the water (H2S, NH4+, CH4). Stable isotope data has shown that the biological communities found in sulfidic caves are not dependent on carbon fixation in green plants that use light energy in the process of photosynthesis. Special adaptations have been identified in some of these inhabitants that allow them to cope with the adverse environmental conditions such as toxicity of H2S, hypoxia, and extreme pH values. Symbiotic associations between crustaceans, protozoa, and sulfide oxidizing bacteria were discovered in several sulfidic caves. New species of microorganisms have also been described from these unusual subsurface environments.

Unusual microbiomes have recently been discovered in dry caves that contain chemoclines between heavy volcanic gasses dominated by CO2, but also containing H2S and CH4, and atmospheric air that floats on top of the volcanic gas emissions. Unique sulfur mineralization, microbial biofilms containing new species of bacteria that thrive at extremely pH values, symbiotic relationships between bacteria and fungi have been discovered in Sulfur Cave in Romania, Bosoletto Cave in Italy, and Sousaki caves in Greece. The extreme life conditions encountered in these caves are of special interest to astrobiologists using these caves as a model for better understanding conditions that life may be present in on other planets and celestial bodies in our Solar System and beyond.
Comparative analysis of lampenflora in two show caves in Serbia
Authors: Popović Slađana , Nikolić Nataša , Pećić Marija , Anđelković Ana , Subakov Simić Gordana
Published: July 2022

Nowadays, caves are increasingly being transformed into tourist attractions by constructing paths, electricity, water infrastructure, and the introduction of light, thereby becoming affected by various disturbances that alter their inherent equilibrium. Conservation of these sensitive environments should be a priority from the moment of their opening. All parameters, including the potential changes around artificial lights, such as lampenflora, should be monitored. Lampenflora in show caves in Serbia has been done for several years in the Lazar and Resava caves, of which the Lazar cave was monitored for over 6 years. This work aimed to compare lampenflora of these two caves, considering samples taken in the year 2021 at the beginning and the end of the official tourist season. Artificial light created favorable conditions for the proliferation of phototrophs, and lampenflora developed in both caves. Considering the community type, epiliths and endoliths were present in both localities. The difference is that endoliths in the Lazar Cave covered more significant areas of substratum, constantly spreading, thus posing a more significant threat to cave substratum and structures. One of the problematic genera was Chlorella, which can switch from an autotrophic to a mixotrophic, and finally to a heterotrophic lifestyle, thus making lampenflora dangerous and hard to deal with. Lampenflora in the Lazar Cave was developed over a large area of the cave substratum, while in Resava Cave, it was usually localized near artificial lights. When caves were compared based on phototrophic microorganism composition, using multivariate analysis, all morphological groups of Cyanobacteria (coccoid, simple trichal, and heterocystous) were more related to the Resava cave and Chlorophyta and Bacillariophyta to the Lazar Cave (based on diversity and number of sampling sites on which they are found). In the Lazar and Resava cave, Cyanobacteria dominated at the beginning of the tourist season and Chlorophyta at the end. Mosses were present, too, with the difference that the moss protonema was more characteristic of Lazar Cave in many places. In contrast, developed mosses were frequently found in Resava Cave near reflectors. In addition to the analysis of phototrophic microorganisms, ecological parameters, primary production, and biofilm parameters were measured, showing seasonal or sampling site variations. We hope that monitoring will be performed more regularly in the future and that it will include a more significant number of show caves for their conservation.
The morphology of the colonizers of the springs from the down-under
Authors: Biró Anna , Balázs Gergely , Fišer Žiga , Herczeg Gábor , Fišer Cene
Published: July 2022

Transition from surface to subterranean environment generally results in easily detectable morphological changes, generally referred as troglomophism. Although the cave colonisation history of species can differ considerably, in certain cases there is a possibility to directly examine the cave-induced morphological and life history changes, as some of the troglobiont and stygobiont species still have closely related surface species. A less common and therefore less known phenomenon is the invasion in the opposite direction, when cave-adapted species establish stable populations (and later, new species) in surface or surface-connected (ecotonal) habitats. A great model taxon to study if morphological changes occur in such cases is the Niphargus genus, which primarily comprises subterranean species, although some species successfully colonised surface or ecotonal habitats.

To get insight of morphological changes and whether these changes were affected by sex, we measured 15 functional morphological traits on 488 individuals from both sex of eight Niphargus species, out of which four inhabit ecotonal (spring) habitats, while the other four are exclusively subterranean. We analysed our data trait-by-trait with linear mixed models. We found that colonising the “new” habitat did not demonstrably affect morphology. In contrast habitat dependent sexual dimorphism was found in case of the 2nd gnathopods’ coxa. Besides the aforementioned habitat dependent sexual dimorphism, we found sexual dimorphism in case of 11 out of the 15 traits. Based on our result we can assume that morphological changes might happen in the course of the colonisation of the novel habitat, but they are not as unambiguous as when surface species colonise caves. It is also possible that although we consider springs as ecotone or even surface habitats, they might be feasible for subterranean species without striking morphological changes as they do not meet selection forces strikingly different from those present in caves.
The role of phenotypic plasticity in the evolution of cave-dwelling animals
Authors: Bilandžija Helena
Published: July 2022

The surface ancestors of subterranean species are often hypothesized to possess pre-adaptations that enable them to successfully initiate colonization of caves. Nocturnal habits and the use of microhabitats such as the underside of rocks or leaf litter are two simple examples. However, there are many exceptions, and a mechanistic explanation for the evolution of a whole range of troglomorphic adaptations has yet to be found. To shed light on the phenotypic and molecular changes that accompany the early stages of cave colonization, we experimentally exposed the most closely related surface species or population of several cave-dwelling species including fish and crustaceans, from the earliest embryonic stage possible, to constant darkness, the single environmental condition characteristic of all subterranean habitats. Our results show that darkness induced a surprisingly large number of phenotypic changes, many of which resembled troglomorphic adaptations found in their respective cave-dwelling relatives (for example changes in fat content). However, some changes were contrary to what is considered adaptive in darkness, such as increased body pigmentation and enhancement in visual system, opposite to the two iconic features of troglomorphy. Overall, we conclude that phenotypic plasticity is an important mechanism for the rapid initiation of changes that may be favored or targeted by natural selection during critical initial steps in the evolution of cave-dwelling species.
Preliminary study on differences characterizes the populations of olm (Proteus anguinus) in cave and those found in epigean environment
Authors: Barzaghi Benedetta , Ficetola Francesco Gentile , Mauri Edgardo , Restaino Marco , Lombardi Bianca , Manenti Raoul
Published: July 2022

The olm (Proteus anguinus) is considered the most representative example of all the stygobiont fauna. Nevertheless, it is also reported in some spring habitats of Friuli Venezia Giulia (North-eastern Italy). Springs are intriguing habitats that border two strongly distinct environments: surface and underground. They may provide distinct environmental pressures to stygobiont animals promoting new adaptations.

The aim of this study is to verify if there are differences in the structural morphology of the head and in the presence of melanin in the skin between the olms that are found in caves compared to the individuals found in the external environment.

During 2021, 28 olms, 18 from underground habitats and 10 from external sites, were photographed in standard conditions with a metric reference. For each individual, only the cephalic region has been considered. The pictures were processed using TPSdig software. For each picture we placed 2 landmark homologues, matching the emergence of the gills branches, and 48 semi-landmark to define the contour of the head. With regard to melanin 2 mm of skin were removed from the tail of the olm and analyzed through a spectrophotometer. The results indicate a significant effect of the environment on the shape of the olm’s head, in fact the shape of the head appears more elongated in the front and narrower in the parietal region in the olms coming from the hypogean environment. In addition, the olms that use the epigean environment show higher melanin levels in their skin.

These findings provide a first evidence of differences occurring between olm populations/sub-populations living in caves and those exploiting surface habitats.
Spatial genetic structure of Dinaric cave-dwelling spiders
Authors: Pavlek Martina , Gauthier Jérémy , Arnedo Miquel , Tonzo Vanina , Bilat Julia , Alvarez Nadir
Published: July 2022

Caves put strong constraints on organisms living there, which results in acquisition of variety of troglomorphic traits, most obvious ones being depigmentation and degradation of visual system (Christiansen 2012). Cave habitats are considered fragmented, and the animals living there face limited connectivity between potential habitats (Barr 1967, Bregović and Zagmajster 2016, Trontelj 2018). Additionally, once adapted to underground conditions, cave-dwellers are thought to be unable to use the surface for dispersal, thus demonstrating population dynamics similar to those of the species found in islands (Barr and Holsinger 1985). We compared the population genetic structure of several cave spider species with different biology and ecology from different caves in the Dinarides. Namely, depigmented and anophthalmic Dysderidae species which were never collected outside caves, and several species from the genus Troglohyphantes, which exhibit different levels of troglomorphisms and dependency on cave habitat (some, like T. excavatus and T. kordunlikanus, can be occasionally found in surface habitats). Additionally, Dysderidae are wandering active hunters, while all Troglohyphantes species spin webs. In our study, we applied a hybridization-capture approach, i.e., HyRAD (Suchan et al. 2016) to extract and capture DNA from historical samples. We compared the population genetic structures among the species, and studied isolation by distance, and identified contrasted genetic structures related to the biology and ecology of each species. We identified a deeper population structuring and more pronounced patterns of isolation by distance in the highly troglomorphic species compared to the less troglomorphic ones. Species that can occasionally be found in surface habitats showed less structured populations compatible with higher dispersal ability. Additionally, we detected several common breaks in gene flow for most studied species, some of which can be explained by geographic and geologic features.
Different components of interconnected karst environment select for highly distinct microbial communities
Authors: Singh Anusha , Shabarova Tanja , Bulzu Paul
Published: July 2022

Karst environments, formed by dissolution of rocks, present a unique opportunity to study groundwater and surface water as a single dynamic system. We aimed to explore the hydrological connections and identify shared microbiome between different components of this complex landscape (terrestrial, surface-subsurface freshwater networks and two different lake strata) on example of karst landscape at north shore of Lake Thun (CH).

52 samples from soil and 87 from the freshwater network were collected during low hydrological conditions. Additionally, 43 samples from 13 different lakes across Europe were included in the analysis. A 16S rRNA gene amplicon analysis revealed highly homogenous lake communities dominated by typical lake microbes represented by members of Alphaproteobacteria, Gammaproteobacteria and Actinobacteria. On the contrary, communities in soils and surface and subsurface water were observed to be highly heterogenous within the karst landscapes. Soil samples built two robust groups that corresponded to alkaline and acidic pH values associated with two types of bedrocks. Alkaline soils had higher abundance of Gammaproteobacteria and Alphaproteobacteria, while acidic soils were dominated by Acidobacteria. Alkaline cluster was better connected with aquatic environments and shared genotypes from the families Nitrosomonadaceae and Nitrospiraceae with cave sediments and lake hypolimnia, that implied ammonia and nitrite oxidation as important chemotrophic processes in light depleted environments. Rhodoferax, Limnohabitans and Sediminibacterium were shared within subsurface network and lakes. Single Rhodoferax genotype was detected in all aquatic environments. Additionally, we observed that lineages from the families Pirellulaceae and Gemmataceae (phylum Planctomycetota) were alternatively distributed in both soil clusters and lakes. A similar pattern was observed in subsurface aquatic components and deeper lake strata within family Methylophilaceae, where Methylotenera was extensively replaced by Methylopumilus. This indicates that despite high hydrological connectedness between different karst landscape components, deterministic selective factors seem to prevail in the community assemblies.
Groundwater contamination and human health risk assessment in the main karst areas of Romania
Authors: Moldovan Ana , Torok Anamaria , Kovacs Eniko , Mirea Ionut-Cornel , Levei Erika , Moldovan Oana Teodora
Published: July 2022

Long-term monitoring reveals the temporal evolution of groundwater chemistry and the potential human health risk posed by the use of contaminated waters (Giri and Singh 2015). Groundwater aquifers are an important source of drinking water in Romania. This study was conducted to appraise the groundwater chemistry and the potential non-carcinogenic risks for human health associated with the groundwater consumption through oral and dermal pathways. In order to achieve this aim, 193 samples were collected from 29 groundwater sources in the main karst areas of Romania during 2019-2021. A total of 15 parameters were analyzed (F-, Cl-, SO42-, NO3, Ca, Na, K, Mg, Fe, Mn, Cu, Zn, Ni, Cr, and As) and compared with the World Health Organization standards for drinking water (WHO 2017). The heavy metals pollution index showed that no groundwater samples had detectable levels of metal contamination, while the heavy metal evaluation index revealed that 4 out of 29 groundwater sources were classified as contaminated: 3 sources with a medium level of pollution and 1 source with a high level of pollution, indicating a potential risk for human health. The human health risk for oral exposure indicated a potential non-carcinogenic risk only in the karst area from South Dobrogea. The non-carcinogenic risk posed by nitrates is higher than that posed by metals in the aquifers from South Dobrogea. Therefore, control and remedial actions should be taken to ensure appropriate water quality for the locals using the contaminated water sources.
Insights into the Eucyclops graeteri species complex (Copepoda, Cyclopidae) — the case of sulphidic groundwaters of Mangalia (Southern Dobrogea, Romania)
Authors: Pop Maria , Ștefan Andrei , Boancă Filip , Stoch Fabio , Iepure Sanda
Published: July 2022

Members of the Eucyclops graeteri species complex are widely distributed in European groundwaters and share some morphocharacters such as:

a long aesthetasc on the ninth segment of female antennula,

short or very reduced spinule row ("serra") on furcal rami,

lateral hairiness of 5th thoracic somite strongly reduced, and

few or no hairs on the distal margin of the intercoxal sclerite of 4th legs pair.

a long aesthetasc on the ninth segment of female antennula,

short or very reduced spinule row ("serra") on furcal rami,

lateral hairiness of 5th thoracic somite strongly reduced, and

few or no hairs on the distal margin of the intercoxal sclerite of 4th legs pair.

All these characters are subject to strong selective pressure in the underground environment; therefore, the study of molecular markers is needed to better define the taxonomy and phylogeny of this species group. The Southern Dobrogea region in Romania conceals dark, isolated, and sulfide-rich aquifers, accessible through artificial wells, springs, and the Movile Cave. The chemoautotrophically-based Movile Cave hosts a member of the E. graeteri complex, described several years ago as a subspecies (E. graeteri scythicus Plesa, 1989). The morphological and molecular analyses performed on specimens of this species complex collected from Southern Dobrogea revealed new records for E. graeteri scythicus both in sulfidic and non-sulfidic artificial wells dug near the cave as well as a species putatively new to science collected in three sulfidic wells from Mangalia. Mitochondrial markers allocated the Movile Cave population in a distinct clade within the genus Eucyclops, Eucyclops serrulatus s.l. being the closest taxon. The putative new species belongs to a different clade within the subfamily Eucyclopinae, raising doubts on the monophyly of this species complex. Furthermore, our investigations revealed the occurrence of ectosymbiont sulfur-oxidizing Thiothrix bacteria associated with E. graeteri scythicus suggesting that this putative symbiosis could allow this taxon to better cope with sulphidic-rich environments. These unique sulfidic groundwater environments therefore provide an interesting model system in which to study the taxonomy of copepods and their adaptation to very harsh environmental conditions.