This paper presents a review of the recent advances in the field of substrate integrated waveguide (SIW) filters, with particular emphasis on the techniques adopted to increase the out-of-band rejection of the filters and on the miniaturization strategies. After an overview of classical approaches to introduce transmission zeros in SIW filters, a number of recently introduced techniques are presented

This paper describes the outcome of the “Small user TErminal multi band DIplexer” project where the goal is the validation of novel SMD-compliant planar diplexer. The real application scenario concerns an integrated multi-band radio terminal for ground-segment satellite links. The advantageous and novel approach involves the simultaneous use of three different well-established concepts: a microstrip

An efficient analysis of time-modulated array (TMA) toward realizing less-attenuating radiation patterns with simultaneously suppressed sidelobe and sidebands is presented in this paper. In this framework, an optimal outer element-controlled time sequence is derived. The proposed time scheme, along with optimized array excitations, is profitably applied for the desired solution. TMAs are considered

To solve the problems of low gain, narrow bandwidth, and poor radiation directivity of conventional ground penetrating radar antenna, this paper proposes an ultra-wideband and high-gain antipodal tapered slot antenna (ATSA) with planar metamaterial lens. As a constituent part of this lens, a new non-resonant metamaterial unit cell is introduced and analyzed by the full-wave simulation tool. The single-layer

The structure of faults beneath Salt Lake City, Utah, shows how the ground could liquefy during a shaking.

‘Superscattering’ material is used to construct a mini-doorway that is invisible in the microwave portion of the spectrum.

Aerial images boast a level of detail that could help the rover navigate to features of scientific interest.

As the world recovers, students still need help to get back on track, say Ruth Gotian and Christine Pfund.

Scientists praise the budget boost slated for the National Science Foundation, but worry the legislation could dampen international collaborations.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to evolve around the world, generating new variants that are of concern based on their potential for altered transmissibility, pathogenicity, and coverage by vaccines and therapeutics1–5. Here we report that 20 human sera, drawn 2 or 4 weeks after two doses of BNT162b2, neutralize engineered SARS-CoV-2 with a USA-WA1/2020 genetic

Food bags, drink bottles and similar items account for the biggest share of plastic waste near the shore.

Cases of dengue fever plummeted in a trial of modified virus-resistant mosquitoes. Plus, four urgent questions about long COVID and clues to the mysterious origins of fast radio bursts.

In science news around the world, despite past safety concerns, Brazilian health authorities decide to allow the importation of Sputnik V, the Russian-made vaccine against the pandemic coronavirus. A strategy for fighting dengue fever using bacteria-armed mosquitoes passes its most rigorous test yet: a randomized controlled trial in Indonesia. In its first year of observation, a radio telescope in

When NASA announced it would spend $1 billion developing two new missions to Venus—the agency's first visits in decades to Earth's hothouse twin—planetary scientists were elated, and not just because a long wait had ended. A dramatic shift in thinking about the planet over the past few years has made a visit even more enticing. Venus was once thought to have boiled off all its water almost as soon

As President Joe Biden's newly installed science adviser, Eric Lander will help shape the new administration's expansive vision for science. But he will also face divisive issues leftover from the previous administration, including tougher enforcement of U.S. government requirements that scientists disclose foreign sources of funding. The government can do better than the current confusing mélange

The antibody aducanumab this week became the first new Alzheimer's disease drug approved in the United States since 2003, and the first ever that aims to interfere with the underlying disease process. In a controversial decision, the U.S. Food and Drug Administration overruled its advisers to approve aducanumab, an intravenously delivered antibody developed by Biogen and marketed as Aduhelm, based

Scientists are unraveling how our organs talk to the brain and how the brain talks back. That two-way communication, known as interoception, encompasses a complex system of nerves and hormones, including the vagus nerve, a massive network of fibers that travel from nearly every internal organ to the base of the brain and back again. Scientist have long known the vagus nerve carries signals between

Nicotinamide adenine dinucleotide (NAD+) is an essential metabolic co-factor that is central to energy metabolism. During aging, obesity, and diabetes, NAD+ concentrations in cells decline. NAD+ is synthesized de novo from tryptophan precursors, from nicotinic acid through the Preiss-Handler pathway, or from nicotinamide through the salvage pathway. The rate-limiting enzyme in the salvage pathway,

The Haber-Bosch process converts nitrogen (N2) and hydrogen (H2) into ammonia (NH3) over iron-based catalysts. Today, 50% of global agriculture uses Haber-Bosch NH3 in fertilizer. Efficient synthesis requires enormous energy to achieve extreme temperatures and pressures, and the H2 is primarily derived from methane steam reforming. Hence, the Haber-Bosch process accounts for at least 1% of global greenhouse

Imagine a choice between two gambles: getting $100 with a probability of 20% or getting $50 with a probability of 80%. In 1979, Kahneman and Tversky published prospect theory (1), a mathematically specified descriptive theory of how people make risky choices such as these. They explained numerous documented violations of expected utility theory, the dominant theory at the time, by using nonlinear psychophysical

The adult mammalian brain retains the capacity to generate new neurons and glia, a feature that is important for learning, memory, and response to injury (1). Neural stem cells (NSCs) in germinal regions of the adult brain, such as the ventricular-subventricular zone (V-SVZ) and the dentate gyrus of the hippocampus, are a major source of new neurons and glia (1). Glia, including astrocytes, oligodendrocytes

Antimicrobial resistance (AMR) is the silent pandemic. It has been steadily increasing over many years and threatens to halt the practice of modern medicine. By 2050, the annual number of worldwide deaths due to AMR will be ∼10 million, with an estimated economic impact of 100 trillion USD (1). The World Health Organization, United Nations, and governments worldwide agree that plans for surveillance

Family separation—whether caused by armed conflict, repressive regimes, disasters, or immigration policies—traumatizes children and parents and can have long-term impacts on physical and mental health (1). It is therefore imperative to develop and deploy policies and tools to support prompt and safe family reunifications and address wrongful government-imposed separations. Given the particular legal

Plants synthesize many diverse small molecules that affect function of the mammalian central nervous system, making them crucial sources of therapeutics for neurological disorders. A notable portion of neuroactive phytochemicals are lysine-derived alkaloids, but the mechanisms by which plants produce these compounds have remained largely unexplored. To better understand how plants synthesize these

Anyone who has an invisible illness: Emily Abel sees you. Abel knows the dual anguish of suffering from an invisible illness and of responding to people who fail to fully recognize this suffering. For decades, she experienced persistent fatigue and intense shame about it. In Sick and Tired, Abel comes to terms with this shame through a personal history of "cultural values" in modern white America.

The success of Seven Brief Lessons on Physics and The Order of Time has made theoretical physicist Carlo Rovelli a household name. In his new book, Helgoland, Rovelli offers to the general public his interpretation of quantum mechanics, arguing that it solves the theory's paradoxes by so profoundly redefining our notion of reality that it erases the ineffable mind-body dichotomy.

Emergent resistance to all clinical antibiotics calls for the next generation of therapeutics. Here we report an effective antimicrobial strategy targeting the bacterial hydrogen sulfide (H2S)–mediated defense system. We identified cystathionine γ-lyase (CSE) as the primary generator of H2S in two major human pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, and discovered small molecules

How eukaryotic cells assess and maintain sizes specific for their species and cell type remains unclear. We show that in the Arabidopsis shoot stem cell niche, cell size variability caused by asymmetric divisions is corrected by adjusting the growth period before DNA synthesis. KIP-related protein 4 (KRP4) inhibits progression to DNA synthesis and associates with mitotic chromosomes. The F BOX-LIKE

Coherent optical excitations in two-dimensional (2D) materials, 2D polaritons, can generate a plethora of optical phenomena that arise from the extraordinary dispersion relations that do not exist in regular materials. Probing of the dynamical phenomena of 2D polaritons requires simultaneous spatial and temporal imaging capabilities and could reveal unknown coherent optical phenomena in 2D materials

Ammonia (NH3) is a globally important commodity for fertilizer production, but its synthesis by the Haber-Bosch process causes substantial emissions of carbon dioxide. Alternative, zero-carbon emission NH3 synthesis methods being explored include the promising electrochemical lithium-mediated nitrogen reduction reaction, which has nonetheless required sacrificial sources of protons. In this study,

Extending the framework of statistical physics to the nonequilibrium setting has led to the discovery of previously unidentified phases of matter, often catalyzed by periodic driving. However, preventing the runaway heating that is associated with driving a strongly interacting quantum system remains a challenge in the investigation of these newly discovered phases. In this work, we utilize a trapped-ion

We explored the bonding properties of the quantum corral (a circle of 48 iron atoms placed on a copper surface) reported by Crommie et al. in 1993, along with variants, as an artificial atom using an atomic force microscope (AFM). The original corral geometry confines 102 electrons to 28 discrete energy states, and we found that these states can form a bond to the front atom of the AFM with an energy

Spiral galaxies have distinct internal structures, including a stellar bulge, a disk, and spiral arms. It is unknown when in cosmic history these structures formed. In this study, we analyzed observations of BRI 1335–0417, an intensely star-forming galaxy in the distant Universe, at a redshift of 4.41. The [C ii] gas kinematics shows a steep velocity rise near the galaxy center and has a two-armed

Quiescent neural stem cells (NSCs) in the adult mouse ventricular-subventricular zone (V-SVZ) undergo activation to generate neurons and some glia. Here we show that platelet-derived growth factor receptor beta (PDGFRβ) is expressed by adult V-SVZ NSCs that generate olfactory bulb interneurons and glia. Selective deletion of PDGFRβ in adult V-SVZ NSCs leads to their release from quiescence, uncovering

Predicting and understanding how people make decisions has been a long-standing goal in many fields, with quantitative models of human decision-making informing research in both the social sciences and engineering. We show how progress toward this goal can be accelerated by using large datasets to power machine-learning algorithms that are constrained to produce interpretable psychological theories

Hedgehog proteins govern crucial developmental steps in animals and drive certain human cancers. Before they can function as signaling molecules, Hedgehog precursor proteins must undergo amino-terminal palmitoylation by Hedgehog acyltransferase (HHAT). We present cryo–electron microscopy structures of human HHAT in complex with its palmitoyl–coenzyme A substrate and of a product complex with a palmitoylated

Viruses are ubiquitous pathogens of global impact. Prompted by the hypothesis that their earliest progenitors recruited host proteins for virion formation, we have used stringent laboratory evolution to convert a bacterial enzyme that lacks affinity for nucleic acids into an artificial nucleocapsid that efficiently packages and protects multiple copies of its own encoding messenger RNA. Revealing remarkable

In rodents, obesity and aging impair nicotinamide adenine dinucleotide (NAD+) biosynthesis, which contributes to metabolic dysfunction. Nicotinamide mononucleotide (NMN) availability is a rate-limiting factor in mammalian NAD+ biosynthesis. We conducted a 10-week, randomized, placebo-controlled, double-blind trial to evaluate the effect of NMN supplementation on metabolic function in postmenopausal

The 2021 Gordon Research Conference schedule was published on pages 1230 to 1233 of this issue of the print version of Science. The current schedule can also be found online at www.grc.org/.

A decade after the first report, the family of two-dimensional (2D) carbides and nitrides (MXenes) includes structures with three, five, seven, or nine layers of atoms in an ordered or solid solution form. Dozens of MXene compositions have been produced, resulting in MXenes with mixed surface terminations. MXenes have shown useful and tunable electronic, optical, mechanical, and electrochemical properties

Next-generation tissue-based biomarkers for immunotherapy will likely include the simultaneous analysis of multiple cell types and their spatial interactions, as well as distinct expression patterns of immunoregulatory molecules. Here, we introduce a comprehensive platform for multispectral imaging and mapping of multiple parameters in tumor tissue sections with high-fidelity single-cell resolution

Ecological resilience is the magnitude of the largest perturbation from which a system can still recover to its original state. However, a transition into another state may often be invoked by a series of minor synergistic perturbations rather than a single big one. We show how resilience can be estimated in terms of average life expectancy, accounting for this natural regime of variability. We use

X-inactive specific transcript (Xist) RNA directs the process of X chromosome inactivation in mammals by spreading in cis along the chromosome from which it is transcribed and recruiting chromatin modifiers to silence gene transcription. To elucidate mechanisms of Xist RNA cis-confinement, we established a sequential dual-color labeling, super-resolution imaging approach to trace individual Xist RNA

On 7 Feb 2021, a catastrophic mass flow descended the Ronti Gad, Rishiganga, and Dhauliganga valleys in Chamoli, Uttarakhand, India, causing widespread devastation and severely damaging two hydropower projects. Over 200 people were killed or are missing. Our analysis of satellite imagery, seismic records, numerical model results, and eyewitness videos reveals that ~27x106 m3 of rock and glacier ice

Understanding the response of Himalayan-Karakoram (HK) rivers to climate change is crucial for ~1 billion people who partly depend on these water resources. Policymakers tasked with the sustainable water resources management for agriculture, hydropower, drinking, sanitation, and hazards require an assessment of rivers’ current status and potential future changes. This review demonstrates that glacier

Despite their partial ionic nature, many layered diatomic crystals avoid internal electric polarization by forming a centrosymmetric lattice at their optimal van-der-Waals stacking. Here, we report a stable ferroelectric order emerging at the interface between two naturally-grown flakes of hexagonal-boron-nitride, which are stacked together in a metastable non-centrosymmetric parallel orientation.

Gemma Derrick revisits calls for a better research culture.

A trove of new detections suggests that the bursts could be the result of at least two separate astrophysical phenomena.

Mass vaccination drives in several countries are providing new data on the extent to which adult vaccination protects children — but the conclusions are mixed.

A highly invasive weed might owe some of its success to easier access to carbon, a key component of the weed’s toxin.

The coronavirus disease 2019 (COVID-19) pandemic has raged for more than a year in the United States, upending life as we knew it. Nevertheless, we have seen incredibly rapid advances in vaccines, therapeutics, and diagnostic testing technology. There is tremendous need and economic interest in reopening our businesses and schools and in resuming gatherings for entertainment and sporting events. To

Social scientists and community advocates have expressed concerns that many social and cultural impacts important to citizens are given insufficient weight by decision makers in public policy decision-making. In two large cross-sectional surveys, we examined public perceptions of a range of social, cultural, health, economic, and environmental impacts. Findings suggest that valued impacts are perceived

DNA replication is dramatically slowed down under replication stress. The regulation of replication speed is a conserved response in eukaryotes and, in fission yeast, requires the checkpoint kinases Rad3ATR and Cds1Chk2. However, the underlying mechanism of this checkpoint regulation remains unresolved. Here, we report that the Rad3ATR-Cds1Chk2 checkpoint directly targets the Cdc45-MCM-GINS (CMG) replicative

Global cooling and glacial–interglacial cycles since Antarctica’s isolation have been responsible for the diversification of the region’s marine fauna. By contrast, these same Earth system processes are thought to have played little role terrestrially, other than driving widespread extinctions. Here, we show that on islands along the Antarctic Polar Front, paleoclimatic processes have been key to diversification

Galanin receptor1 (GalR1) transcript levels are elevated in the rat ventral periaqueductal gray (vPAG) after chronic mild stress (CMS) and are related to depression-like behavior. To explore the mechanisms underlying the elevated GalR1 expression, we carried out molecular biological experiments in vitro and in animal behavioral experiments in vivo. It was found that a restricted upstream region of

A once in a century new viral outbreak, COVID-19, has caused unfathomable numbers of deaths, toward 4 million. Yet an ancient disease, malaria, endemic to the residents of more than half of Earth, is even more devastating than this pandemic over time: It caused about 12 million deaths in the last 20 y alone, with estimates of tens of millions of deaths in the preceding three decades (1). Arguably the

Patients with severe COVID-19 infection exhibit a low level of oxygen in affected tissue and blood. To understand the pathophysiology of COVID-19 infection, it is therefore necessary to understand cell function during hypoxia. We investigated aspects of human monocyte activation under hypoxic conditions. HMGB1 is an alarmin released by stressed cells. Under normoxic conditions, HMGB1 activates interferon